Michael Fassbender: "300" (2006)
Before starring as Magneto in X-Men movies, Fassbender (at right) was a superhero of another kind. He played Stelios in Zach Snyder's stylized take on the Battle of Thermopylae during the Greco-Persian Wars in 480 B.C.
Kristen Stewart: "Into the Wild" (2007)
At 16-years-old Stewart appeared in Sean Penn's Into the Wild starring Emile Hirsch as Chris McCandless. They become friends at one of Chris' many stops during his odyssey that takes him all over the U.S. She falls for him, but the romance is not to be.
Amy Adams & Ellen Pompeo: "Catch Me If You Can" (2002)
Both Adams (left) and Pompeo impressed in small roles in Steven Spielberg's Catch Me If You Can. They each play love interests of Leonardo DiCaprio's character Frank Abagnale, a teenage con man who evades capture for years.
Ryan Gosling: "Remember the Titans" (2000)
Jake Gyllenhaal: "City Slickers" (1991)
A 10-year-old Gyllenhaal appeared as Billy Crystal's son in City Slickers. It was his first role and he has a great scene where he's mortified by his father's performance at his school's career day.
Philip Seymour Hoffman: "Scent of a Woman" (1992)
Hoffman (left) plays George, "hiding in big daddy's pockets." As Al Pacino's Colonel Slade pointedly remarks. George is a classmate of Charlie's (Chris O'Donnell) who tries to escape trouble by ratting out his friends.
Amanda Seyfried: "Mean Girls" (2004)
Mean Girls die hards are well aware of Ms. Seyfried's presence in the Tina Fey-penned comedy, but the casual movie goer may not be. Amanda played the third Plastic, Karen, behind Rachel McAdams and Lacey Chabert.
Seth Rogen: "Donnie Darko" (2001)
Rogen's first feature role was as Ricky Danforth in Richard Kelly's cult classic Donnie Darko. You'd never guess the guy could be funny from his meatheaded performance.
Vanessa Hudgens: "Thirteen" (2003)
Hudgens (right) got her first shot at a speaking role in a movie in Catherine Hardwicke's coming of age drama, Thirteen. She plays a good girl who's surprised when her friend, Tracy (Evan Rachel Wood), starts acting very different.
Natalie Portman: "Heat" (1995)
Everyone knows Portman stole the show as a young hitwoman-in-training in 1994's Léon, but the following year she was in a much higher profile movie starring Al Pacino and Robert DeNiro. She plays Pacino's girlfriend's daughter, a small but demanding role for the future star.
Jonah Hill: "I Heart Huckabees" (2004)
Hill landed his first role in David O. Russell's existential comedy, I Heart Huckabees. He plays the adopted brother of Stephen (Ger Duany), the Nigerian doorman at the center of three coincidences.
Carey Mulligan: "Pride & Prejudice" (2005)
In her first role, Mulligan (right) was cast as the second youngest Bennet sister in Joe Wright's adaptation of Jane Austen's beloved novel Pride and Prejudice. Also appearing: a young Jena Malone.
Steve Buscemi: "Pulp Fiction" (1994)
Buscemi has a cameo as a Buddy Holly impersonator/waiter at Jack Rabbit Slim's, Ms. Mia Wallace's (Uma Thurman) favorite five dollar milkshake spot.
Jack Black: "Dead Man Walking" (1995)
Black's career is filled with tiny roles in weird movies you may have forgotten about (Bio-Domecomes to mind), but the weirdest is his appearance in the somber Dead Man Walking. Black plays one of Matthew Poncelet's (Sean Penn) three little brothers.
Joseph Gordon-Levitt: "A River Runs Through It" (1992)
Levitt was a prolific child actor and well-seasoned by the time he nabbed a small role in Robert Redford's period drama about a Montana fly fishing family. He was only 10 during filming.
Brad Pitt: "True Romance" (1993)
Pitt's cameo in True Romance is, admittedly, a little hard to forget but we're including him anyway. He shows off a new side, playing the world's laziest stoner, Floyd. He's priceless with his Fritos and honey bear bong.
Jude Law & Adam Scott: "The Aviator" (2004)
Law (right) portrayed devilish actor Errol Flynn and Scott (left) played Howard Hughes' flamboyant press agent, Johnny Meyer, in The Aviator. They only appear in a couple scenes but they each capture the fast-talking ways of the roaring '20s in Hollywood.
Scarlett Johansson: "The Horse Whisperer" (1998)
How could anyone not remember that face? Johansson had her first major role in The Horse Whisperer. She plays a damaged young girl who loses her leg in an accident and, quite literally, gets back up on a horse.
Ben Affleck & Matt Damon: "School Ties" (1992)
Childhood best buds (and distant cousins) Affleck (left) and Damon's (second from right) first movie together was the boarding school drama School Ties. They also met actor Cole Hauser on the movie and they all reunited on the set of Good Will Hunting five years later.
Vince Vaughn: "Rudy" (1993)
In one of the best football movies ever made, Vaughn plays Jamie O'Hara, a selfish halfback with no heart. He's one of the few players to make fun of the film's hero but, by the end, he comes around.
Bill Paxton: "The Terminator" (1984)
Paxton's (middle) wild eyed craziness fit his small role as "Punk Leader" in The Terminator to a tee. He becomes an early victim of Arnold Schwarzenegger's killing machine after the cyborg arrives in 1984 buck naked and looking for clothes. Paxton also sports a trademark face tattoo and blue spiky hair.
Abigail Breslin: "Signs" (2002)
She's best remembered for her Oscar-nominated performance in Little Miss Sunshine, but Breslin first appeared as Mel Gibson's daughter, Bo, in the alien thriller Signs. She's the key to the movie's secret, or rather, her distaste for "old" water is.
Jada Pinkett Smith: "Menace II Society" (1993)
Pinkett Smith's, née Pinkett, first role came in the ghetto classic Menace II Society. She plays Ronnie, who tries to get Caine, the film's protagonist, to move away with her to a better life in Atlanta.
Johnny Depp: "Platoon" (1986)
It's easy to forget about Depp since Charlie Sheen, Willem Dafoe, and Tom Berenger have Platoon's three lead roles.
Christopher Walken: "Annie Hall" (1977)
Walken's small role as Annie's (Diane Keaton) brother is one of the best scene-stealing parts in any movie. He reveals to Alvy (Woody Allen), "because he's an artist and will understand," that sometimes he fantsizes about yanking his car into oncoming traffic. It makes their ride to the airport very interesting, and hilarious.