When Benedict Cumberbatch was 19 years old, he got good and lost in the Himalayas. No longer a schoolboy in tailcoat and boater, not yet the internationally known star of Sherlock and one of the world’s most unlikely sex symbols, he had taken a gap year before university to get a glimpse of life beyond A-level exams and Sunday chapel.

In a hillside town near Darjeeling, he taught English to Tibetan monks, giving himself a crash course in improvisation as he conjured up instructional games. On weekends off, he would seek adventure: white-water rafting down the Kali Gandaki River, traversing the desert province of Rajasthan. (It was monsoon season everywhere else.) But the mountains beckoned.

So he and three friends caught a bus from Kathmandu. Sherpas were expensive, and they were students traveling on the cheap, so they decided, extremely unwisely, to wing it. Altitude sickness derailed them one by one: their group of four became a group of three, then a group of two. By the third night, Cumberbatch recalls, “I started to have really weird, fucked-up dreams, and felt things were happening in my sleep. I wasn’t sure if I was conscious or awake.”

He and his friend reached a spiritual fork in the road, which happened to be a literal fork in the road: up or down? They chose up. And that’s when they got utterly, hopelessly, bewilderingly lost. They ran out of biscuits. They drank rainwater squeezed out of moss, because they’d read it was safer than river water. As night fell, with their flashlights losing power, they pressed on through the thicket, until they spotted a corrugated-steel roof in the distance: salvation?

Turns out it was an abandoned barn. They threw themselves belly-down on straw and drifted to sleep. That night, they had even more fucked-up dreams, each of them convinced that someone—or something—was rifling through their bags. But when they woke up, there was no one.

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The next morning, they followed the river, hoping it would lead to civilization. They nearly broke their necks slipping down moss-covered boulders. The alpine fog gave way to forest, and leeches stuck to their ankles. They found a path with fresh yak droppings: a good sign. Finally, the trees thinned, and they came to a clearing of terraced pastures and log cabins that looked like something out of The Sound of Music. Running toward the inhabitants, they mimed the international sign for hunger (fingers to open mouths) and were served the best-tasting meal they’d ever had—unwashed greens and a bowl of eggs—after which Cumberbatch immediately got dysentery.

“Ah,” the actor sighs 21 years later, “you take the highs with the lows.”

Cumberbatch is recounting this tale in the lobby of Shutters on the Beach, a five-star hotel in Santa Monica. He’s been staying here all week, doing pickups—minor shots after principal photography is done—for Doctor Strange, the reportedly $165 million fantasy film, in which he plays one of Marvel’s more mind-bending superheroes. He tosses his sunglasses and trilby on the table, then reclines on a canvas-wrapped chair in an off-white T-shirt and trousers, gazing blearily at the bicyclists and roller skaters out on the boardwalk. It’s 11 A.M., and he’s working on no sleep.

Seriously, none. He was out shooting an exterior nighttime sequence until 7:30 in the morning, acting opposite co-stars who weren’t actually there, punctuated by long stretches in the makeup chair during which he struggled to stay awake. “It’s probably, hours-wise, the craziest day’s work, if you can call it a day, I’ve ever, ever done,” he says over an iced coffee. A tiny sparrow has flown into the hotel lobby and is darting around underfoot, its discombobulation mirroring the 40-year-old actor’s. He offers a very English disclaimer: “Fluidity, accuracy, intelligence, humor—all these things might be very odd today. I don’t really know who I am.”

And yet he proceeds to talk in a “Flight of the Bumblebee” sprint, like Sherlock Holmes briskly deconstructing a crime scene. (“Why, it’s obvious.”) On-screen, Cumberbatch’s motormouthed precision and dagger-sharp blue eyes can read as otherworldly, as if he were a slightly more advanced human life-form than the rest of us. If he’s been pigeonholed, it’s for playing socially challenged geniuses, people who compute more than relate: the World War II code breaker Alan Turing (in The Imitation Game, for which he was nominated for an Oscar in 2015), the WikiLeaks mastermind Julian Assange (The Fifth Estate), and, of course, Sherlock, whom he’s played since 2010 in the wildly popular BBC series.

Of Memes and Ben

Being Benedict Cumberbatch means living under a magnifying glass, like a fingerprint under Sherlock’s gaze. Nearly everything he does is captured, catalogued, and obsessed over by an ever widening rabble of fans. Some call themselves Cumberbitches. Or, slightly more P.C. (but not much), Cumberbabes. Perhaps it’s his accentuated Britishness—that Dickensian name, that Brontëan pallor—that renders him a kind of imaginary dress-up doll, a thinking woman’s fetish object. If Laurence Olivier had lived in the age of Tumblr, he might have been the “Internet’s boyfriend,” too.

A good chunk of the Web is now devoted to Cumbergazing, or Cumberfantasizing, or straight-up Cumberstalking. The @CumberbitchesTwitter account, dedicated to “the appreciation of the high cheekboned, blue eyed sexbomb that is Benedict Timothy Carlton Cumberbatch,” has 256,000 followers. There’s a bustling Cumberbitch group on Reddit, which celebrates “ThrowBatch Thursdays.” Biography.com outlined the “8 Essential Qualities of a Cumberbitch,” which include holding “an unofficial bachelor’s degree in Cumber-ology.” In 2014, The London Review of Books published a poem in which the author imagines meeting Cumberbatch at a party. He’s huge in China, where fans refer to Holmes and Watson as Curly Fu and Peanut. A baker in Indonesia makes “cumbercupcakes,” complete with edible figurines.

The Cumberfrenzy can be traced to July 25, 2010, when the first episode of Sherlock aired in the U.K., watched by 7.5 million viewers. Twitter went berserk. Something about Sherlock’s sexlessness—his nearly sociopathic focus on solving crimes, to the exclusion of normal human relations—made him that much more irresistible, as if just the right woman could turn him toward carnality. Or the right man: the series is laden with innuendo about Sherlock and John Watson, played by a cutely befuddled Martin Freeman. Forums of erotic “Johnlock” fan fiction have filled in the blanks. (From a story called “First Times”: “All it took was a glance, and it was like the dam finally broke. They couldn’t hold back anymore. John had stopped, mid-breath, and then his lips were on Sherlock’s.”)

Cumberbatch greets the fan deluge—some of it creative, some of it creepy—with a practiced amusement. On my way to meet him in Santa Monica, I check online for the latest haul. A Twitter user has posted: “Sometimes when I’m sad I picture a shirtless Benedict Cumberbatch slowly eating an apple fritter. Try it!”

When I read this to Cumberbatch, he blushes on cue and says, “Have you tried that? It wouldn’t work for me.” He laughs, a little uneasily. “I’m glad I’m bringing a ray of sunshine to an otherwise dull day, being imagined eating fritters shirtless. But, I don’t know, it makes me giggle. I don’t look at myself in the mirror and go, ‘Yeah, absolutely! I see what they’re saying!’ I see all my faults and everything that I’ve always seen as my faults.”

Strange Days

Of course, not all the attention is so benevolent. Obsession breeds possessiveness, which can breed something darker. Last year, Cumberbatch married the stage director Sophie Hunter, and they had a son, Christopher (nicknamed Kit). “There are people who believe that my wife is a P.R. stunt and my child is a P.R. stunt,” he says, unsure if he should even be bringing this up—he knows that there’s no arguing with conspiracy theorists. “I think really it’s to do with the idea that the ‘Internet’s boyfriend’ can’t actually belong to anyone else but the Internet. It’s impossible he belongs to anyone but me. And that’s what stalking is. That’s what obsessive, deluded, really scary behavior is.”

Doctor Strange will surely add to the hysteria. The film, which opens November 4, will do little to dispel Cumberbatch’s reputation as the go-to guy for super-brains. (As he’s quick to point out, he also enjoys playing “out-and-out dummies,” like the love-struck loser Little Charles in August: Osage County.) Created in 1963, by the same Marvel team that concocted Spider-Man, Doctor Stephen Vincent Strange is a world-famous neurosurgeon whose healing hands are ruined in a car accident. Desperate to regain his skills and the material luxuries they afford, he travels to the exotic city of Kamar-Taj, where he meets a guru known as the Ancient One, played by Tilda Swinton. Trained in the mystic arts, he is reborn, in Cumberbatch’s description, as “the primary sorcerer on earth and the defender of our realm against other-dimensional threats.”

So much for out-and-out dummies.

If his brainiac roles have defined him, he insists that’s just because those are “the characters that pop. They’re the characters that people are in awe of, because they’re a little bit beyond us.” He might as well be describing his own curious appeal: part Mr. Darcy, part cyborg. And yet he isn’t a drag. “Benedict is an extremely nice person to work with,” Swinton says. “Engaged, quick-witted, enthusiastic, kind and relaxed, up for a giggle and properly companionable on long days, self-sufficient, concentrated, yet chock-full of fun.” (Swinton’s casting has drawn accusations of whitewashing, since the character in the comics is an Asian man.)

Cumberbatch is no comic-book geek, though he has trod in fantastical realms before, as the genetically bred Khan (another superhuman!) in Star Trek into Darkness. When some journalists at a Star Trek event told him a few years ago that he’d make a perfect Doctor Strange, he replied, “Doctor What?” He was “lukewarm” about the material at first, thinking the comic too dated: 60s occultism meets Cold War science fiction meets Orientalist pulp. But it put him in the mind of his sojourning teenage self, reading The Tao of Physics and searching for “the godhead within.”

And so, last fall, Cumberbatch caught a plane to Kathmandu, two days after finishing his panic-causing run as Hamlet at London’s Barbican Centre. (Advance tickets sold out within hours, leaving salivating fans to line up down the street.) It was six months after the Nepalese earthquake that had killed more than 8,000 people, and his first time there since his misbegotten trek in the Himalayas. This time, he was the antithesis of a man lost in the wilderness, searching for signs of humanity—humanity would now find him whether he liked it or not.

The first few days, he and the cameras passed through the city unnoticed, thanks to Strange’s “desperate caveman” look: scraggly beard, shambolic clothes. “We did a lot of guerrilla stuff, just walking through markets,” Cumberbatch recalls. The day he arrived, he saw a riverside cremation. Shooting atop the Monkey Temple, he watched “30 Tibetan women wandering around the central stupa with the all-sensitive eye in the middle, dragging their hands on prayer wheels, muttering their puja, their prayers.” It was enchanted, peaceful. But then word got out, and the crew was ambushed by locals with cameras yelling, “Benedict! Benedict!”—or, more often, “Sherlock! Sherlock!”

“There were throngs of people,” recalls Chiwetel Ejiofor, his co-star in Doctor Strange and 12 Years a Slave. “I didn’t know that Sherlockwas big in Kathmandu, but apparently I was wrong.” At one point—preserved on YouTube—Cumberbatch stuck his bearded face out of a window overlooking Lalitpur’s Patan Durbar Square and waved to the crowds; shouts of “Say cheese!” are underscored by a distinctly female group wail. Time ran the headline TURNS OUT BENEDICT CUMBERBATCH CAN’T GO ANYWHERE.

Actors’ Actor

Nothing from his upbringing suggested that his chosen craft would inspire this level of fanaticism. He grew up in Kensington, the only child of Timothy Carlton and Wanda Ventham, both working actors who made careers in commercial theater and British sitcoms. (Timothy Carlton dropped the “Cumberbatch” from his stage name, thinking it too fussy. His son, after starting his career as Benedict Carlton, did the opposite, on advice from an agent.) Ventham, who has a daughter from a previous marriage, was a fixture on the science-fiction series UFO and the BBC comedy Only Fools and Horses. She was a stunner. “Whenever they wanted a glamour girl or someone rather beautiful, they wheeled in Wanda,” says her longtime acquaintance Una Stubbs, who now plays Sherlock’s doddering landlady, Mrs. Hudson; Stubbs recalls running into Ventham on the street and gossiping as four-year-old Benedict tugged at his mother’s dress.

Through his parents, he observed the profession’s ups and downs: “I saw the fallow periods as much as I saw when they were ticking along nicely and getting work.” Dragged to see his mother in yet another chintzy Feydeau farce, he would sniff, “If I see another one of those, I’m going to have to disown you.” Nevertheless, his parents worked doubly hard to send him to Harrow, the elite boarding school. (His paternal grandmother helped with tuition.) Harrow was “obscenely pampering and privileged,” he says—alumni include Cecil Beaton and Winston Churchill—and as the son of actors he didn’t always fit in among the peers and princes. But his first two years there he landed two big Shakespearean roles, both female. “The first time I stepped onstage in front of an all-male public-school crowd was dressed up as queen of the fairies, Titania, with a Cleo Laine wig and a pineapple crown.”

Playing Rugby and cricket insulated him from taunts. But in his final years he dropped sports to focus on acting and painting; his classmates, he says, “presumed that because I was into art I was definitely gay.” After his mind-opening pilgrimage east, he returned to study drama at the University of Manchester and the London Academy of Music and Dramatic Art. He worked at a steady clip, playing Stephen Hawking in a TV biopic and earning an Olivier nomination as Tesman in a West End production of Hedda Gabler. But he envisioned something bigger than his parents’ journeyman careers: “I wanted to do things that they didn’t get the chance to.”

Now that Sherlock has made that possible, he may not be long for the role. Having filmed Season Four, which premieres in January, he does not expect to return to the character “for the immediate future.” Sherlockmade him a meme; The Imitation Game made him an A-lister; Doctor Strangemay yet make him a mega-star.

Role with It

Because he resembles a sun-deprived habitué of the London Library, you wouldn’t peg Cumberbatch as a daredevil, but he has always gravitated toward the edge: motorbiking, skydiving. “He’s definitely a bit of an adrenaline junkie,” says his best friend, Adam Ackland, whom he met while working on the 2008 BBC drama The Last Enemy. (Their production company, SunnyMarch, is developing several Cumberbatch vehicles, including an adaptation of the 1939 suspense novel Rogue Male.) Acting, for Cumberbatch, is another form of thrill-seeking, a way to scale Himalayan summits of the psyche. Hamlet was a kind of Everest, one he seems to have conquered. As the Telegraph critic wrote, “Cumberbatch admirers can take heart, his female devotees are entitled to swoon: in this trial of his acting strength, he emerges, unquestionably, victorious.”

To understand his taste for the extreme, you have to go back to 2004, to a near-death experience even more harrowing than his misadventure in the Himalayas. He was in KwaZulu-Natal, South Africa, filming the BBC mini-series To the Ends of the Earth, and went scuba-diving in Sodwana Bay with two of his co-stars, Theo Landey and Denise Black. As they were returning at night, along a stretch of highway notorious for carjackings, they pulled over with a flat tire. Six armed men jumped them and took their cell phones and credit cards, then forced them back into the car at gunpoint and drove. At one point, Cumberbatch was stuffed in the trunk. “Ben kicked and screamed blue-bloody murder,” Landey recalls.

The robbers stopped under a bridge, where the actors were tied up with their own shoelaces, crouching execution-style. Convinced these were his last moments, Cumberbatch pleaded for his life. After several minutes of silence, he realized the men had left. The actors managed to untie themselves and wandered along the highway until they stumbled across some local women who lent them their phones to call for help.

Rather than retreating into himself, as some might after a trauma, Cumberbatch says the ordeal only intensified his lust for adventure. “I was definitely more impatient to live a life less ordinary,” he says. “I wanted to swim in the sea that I saw the next morning. If you feel you’re going to die, you don’t think you’re going to have all those sensations again—a cold beer, a cigarette, the feel of sun on your skin. All those hit you as firsts again. It is, in a way, a new beginning. But we were on our way back from the first weekend of a scuba-diving training course, so it wasn’t as if I was insular before that. I think it just made me run at it a bit more recklessly.”

The past two years have tempered, or perhaps transmuted, his need for adrenaline. When I ask where he wants to find his next thrill, he says, “It’s a sappy answer, but the truth is I want to seek some thrills at home.” He met Hunter almost two decades ago, at the Edinburgh Festival Fringe, but it took them years to get together. After a courtship that they miraculously managed to keep out of the tabloids, they married Valentine’s Day 2015 on the Isle of Wight. Hunter was pregnant with Kit, who was born that June, two weeks before Cumberbatch began rehearsals for Hamlet. He has since given up motorbiking, to say nothing of jumping out of airplanes.

“Having a baby—it’s massive,” he says. “And on a very unexpected level. Suddenly I understood my parents much more profoundly than I ever had before.” Fatherhood gave him counter-intuitive insight into the most challenging role in the theatrical canon. “I was expecting, with Hamlet, that it might be a hindrance to be a father, because it’s all about being a son. But it’s the opposite. You understand much more about being a son, becoming a father.”

Swinton says, “My fondest impression of him is as a new husband besotted by his girl, and a new father enchanted by his boy.” She doesn’t worry that fame will spoil him: “I think he knows that he wants—and has—a life first and foremost, that his life suits and nourishes him and that it makes the world go round.”

Speaking of which, Cumberbatch has to catch a plane—back to London for a few days, before a much-needed Italian holiday with Sophie and Kit. The sparrow is still flitting around the hotel lobby, suddenly alighting on the chair behind me. “Jesus Christ!,” I yell, embarrassingly startled. But Cumberbatch, unruffled, hops up from his chair, walks over to the terrace door, and props it open with a rubber wedge.

“That might give the bird a chance,” he says, backlit by sunlight.

It seems like a metaphor for something, but Cumberbatch is no trapped bird in need of rescue. Instead, it occurs to me, I’ve just witnessed a would-be meme, a Cumberbitch fantasy in the making.

Sometimes when I’m sad I picture a sleepless Benedict Cumberbatch freeing a tiny sparrow. Try it!