Imagine having to make Cast Away with a first-time actor instead of Tom Hanks. That's essentially the challenge Ang Lee faced in adapting the 2001 best seller Life of Pi, about the teenage son of an Indian zookeeper stranded at sea for 227 days with a Bengal tiger. As the Oscar-winning director puts it, "If you don't have the kid, you don't have the movie." To find his kid, Lee dispatched an "army" of casting agents to India, where they eventually selected a dozen finalists from 3,000 hopefuls. The winner, Suraj Sharma, then 17, had almost no acting experience—he'd just followed his younger brother to the casting call. "He had these goofy glasses on," Lee recalls. "I said, 'Take them off.' There was something there."

Hanging the fate of a big-budget would-be blockbuster on a neophyte sounds like a risky strategy. But according to Lee, Hollywood's preference is for maximum recognizability or none at all. "Totally fresh face or a big movie star," he says. "That's the industry rule." Since the $20 million–a–movie heavyweights are increasingly unable to guarantee box-office success, there's an economic argument for choosing the vastly less expensive newcomer. (See, for instance, Jeremy Irvine, whom Steven Spielberg chose for War Horse in part because he'd never acted in a movie, or Kenny Wormald, a pro dancer with just a few obscure film credits before he starred in the remake of Footloose.) Plus, directors sometimes find it easier to mold a rookie than a more seasoned actor. Casting an unknown (and putting his or her face on a poster) can also be a clever way of generating free publicity: Moviegoers feel like they are making a discovery and pass the word along—think Gabourey Sidibe in Precious.

But the pitfalls are obvious. Kyle MacLachlan recalls suffering a crisis of confidence on his first day shooting Dune with David Lynch in 1983, when he was 24. "I'd never been on a soundstage," he explains. "I'd never seen a camera." To prepare Sharma, in January 2011 Lee whisked him from his home in New Delhi to Taiwan, where he received a crash course in swimming, yoga, and scuba diving, not to mention one-on-one acting classes. After spending 10 months as the action-movie equivalent of Eliza Doolittle, he returned to high school, where, he admits, he found it hard to concentrate. "My entire life became the movie," he says, "so I kind of lost touch with most other things."

Lee has vowed to look after his young star, even referring to himself as Sharma's guru. The actor could end up needing one. After Dune tanked, MacLachlan found himself in the unique position of being on billboards while struggling to get even an audition. "It's difficult to recover from something as catastrophic as that," he says. Adam Shankman, who cast Nikki Blonsky as the lead in his 2007 remake of Hairspray when she was working at a Cold Stone Creamery on Long Island, acknowledges that these plucked-from-obscurity ascents can be challenging to new stars. As a guest judge on So You Think You Can Dance, Shankman regularly advises young talent to "save every penny you made, because when you come out of this experience, you'll be the two worst things in the world: poor and famous." Blonsky went on to work as a makeup artist at a salon in Great Neck, New York.

Sharma is waiting to see how Life of Pi does before choosing his next move, but the young actor has already decided one thing: "I want to make movies—to direct, hopefully, one day." At least he's got the Hollywood mind-set down.

• • •

A Star Is Born
Below, a compilation of eight out-of-the-blue sensations.

Tippi Hedren, The Birds, 1963
Before: A commercial model spotted by Alfred Hitchcock in a soda ad.
After: Struggled to break her exclusive contract after the director grew obsessed with her.

Kyle MacLachlan, Dune, 1984
Before: Toiled in Pacific Northwest regional theater.
After: Couldn't land another job after being slaughtered by critics, until David Lynch cast him again in Blue Velvet.

Ricki Lake, Hairspray, 1988
Before: She'd shot a single episode of the sitcom Kate & Allie before John Waters came calling.
After: Became a talk-show host and weight-loss guru—not to mention a Dancing With the Stars contestant and a home-birth advocate.

Patrick Fugit, Almost Famous, 2000
Before: Had a few TV appearances under his belt, but his performance as Cameron Crowe's youthful alter ego was marketed as his introduction.
After: Has worked steadily, most recently in Crowe's We Bought a Zoo and the HBO film Cinema Verite.

Nikki Blonsky, Hairspray, 2007
Before: Scooped cones at a Cold Stone Creamery on Long Island before being discovered by director Adam Shankman.
After: After a stint as a makeup artist in her native Long Island, joined the cast of NBC's Smash.

Freida Pinto, Slumdog Millionaire, 2008
Before: Anchored a Mumbai-based travel show and modeled for Wrigley's and DeBeers before auditioning for Danny Boyle.
After: Sought out by directors like Woody Allen, Julian Schnabel, and Terrence Malick.

Gabourey Sidibe, Precious, 2009
Before: Worked as a receptionist; was told by Joan Cusack to avoid show business.
After: Parlayed an Oscar nomination into roles in Tower Heist and Showtime's The Big C.

Kenny Wormald, Footloose, 2011
Before: Dancer for Justin Timberlake, among others.
After: Will appear in a mock-reality-TV show about South Boston bros in Hollywood called Massholes.

• • •

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