Justin Timberlake age 14
By eighth grade in Millington, Term., the boy who would grow up to be a music superstar and leading heartthrob was already an attention-getter. "Little girls just surrounded him," recalls his stepfather Paul Harless. In 1989 Timberlake experienced his first taste of stardom as a warmup act for a local lip-synching contest. Four years later he joined TV's The Mickey Mouse Club—along with adolescent colleagues Christina Aguilera and Britney Spears.

Lindsay Lohan age 12
Before Mean Girls, Lohan played twin girls. In 1998 she made her film debut in The Parent Trap and smiled for the cameras in Manhattan. Her newfound stardom "was a lot at once for me," recalls the Long Islander, though she had signed with the Ford modeling agency at age 3 and had already appeared in Gap ads.

Catherine Zeta-Jones age 7
Once little "Cate" enrolled at the private Dumbarton House School in Swansea, Wales, "she practiced hard at dancing and acting, but she always managed to keep up with her homework," says headmaster Aled Thomas. The young hoofer gave up the balancing act at 16, when she left school to tour in the musical The Pajama Game.

Leonardo DiCaprio age 16 & Tobey Maguire age 15
Striking a pose at the 1990 American Youth Awards, the two buddies met when they were both auditioning for the early-'90s TV series Parenthood. DiCaprio got that part, but they costarred in the 1993 drama This Boy's Life. They went on to become box office kings: DiCaprio's Titanic is the highest-grossing movie of all time in the U.S., while Maguire's Spider-Man is a not-too-shabby sixth.

Reese Witherspoon age 15
The Legally Blonde spitfire pauses on the set of her first TV movie Wildflower in 1992. Before graduating from Nashville's exclusive Harpeth Hall School, the debutante—called "Big Words" by friends—had made seven movies. After studying briefly at Stanford, Witherspoon, now 28, abandoned her books for a role in the '98 murder mystery Twilight.

Ben Stiller age 12
Though Ben Stiller was raised by comedians—dad Jerry Stiller (left, with his son in Manhattan) and mom Anne Meara—there was nothing funny about Ben's youth. "I was sort of confused and not that cool," he once told Britain's Observer. "Probably 13 through 19 was not a great period for me." Dreaming of becoming a "serious" director, "I think I was rebelling against my parents," he said. But in time, the 38-year-old embraced light comedy, first on FOX's The Ben Stiller Show in 1992 and then in a string of movies including the upcoming Meet the Fockers.

Colin Farrell age 21
Yup, that's Farrell in 1997, teaching line dancing at the Break for the Border pub in Dublin. And although he's still no stranger to pubs, the 28-year-old did change professions. "I was drinking and smoking and getting lazy," he told Interview magazine. "I thought, 'Maybe it's time to try acting.'" In 2000's Tigerland, Farrell launched his movie career. He's got "that allure, that indefinable something," says the film's director, Joel Schumacher. "In the words of Miss Piggy, 'Some pigs got it, and some don't.'"

Jude Law age 16
When he first auditioned for Britain's National Youth Music Theatre, 13-year-old Law was mistaken for a girl "because of his pretty looks," says NYMT founder Jeremy James Taylor. By 16, he'd proved that he was more than just a pretty face, starring in NYMT's Joseph and the Amazing Technicolor Dreamcoat. "I can't say I've suffered for my looks," the now 31-year-old father of three told Britain's Times, "and that's fine, but I want to be made to work hard."

Donald Trump age 4
Born in 1946 and bred in Queens, Trump got shipped out when his parents enrolled him in the New York Military Academy at age 13. "They sent me away for a little discipline," admits the mogul. "It was tough, yeah, but I had a great time."

Halle Berry age 20
The first African-American woman to win a Best Actress Oscar was the first black contestant from the U.S. to become a Miss World finalist. In 1986, when the international beauty contest first allowed bikinis in the swimsuit competition, Berry paraded before judges in a subdued one-piece—though she had worn a shocking stars-and-stripes bikini to a prepageant luncheon. "She had that quiet confidence to wear anything that's different than anyone else," recalls Miss World organizer Julia Morley. But the former Miss Ohio lost the crown by half a point. Oscar came through less than two decades later.