Before she was Bella Swan in the wildly popular "Twilight" franchise, Kristen Stewart starred opposite Jodie Foster in 2002's "Panic Room" at the age of 12. She also appeared in "Cold Creek Manor" at 13, and "Zathura: A Space Adventure" at 15.
Claire Danes first hit it big when she was 15 in the 1994 version of "Little Women." Then the lead in Baz Luhrmann's 1996 film "Romeo+Juliet" alongside fellow child actor Leonardo DiCaprio when she was just 17.
Christina Applegate was 15 when she was cast in "Heart of the City." She also spent 10 years on "Married with Children" between the ages of 15 and 25.
By the time she was 6, Drew Barrymore had already starred in "E.T.: The Extra-Terrestrial." By the time she turned 18, Barrymore had been in 25 movies and TV shows.
One could argue that because Zac Efron is still practically a child, he has yet to outgrow the "child star" label. However, Efron, shown here at the age of 17 in 2004, began acting at the age of 15 in an episode of Joss Whedon's "Firefly."
Like Zac Efron, Taylor Lautner can technically still be counted as a child star, but Lautner, 11 in this photo, got his first acting gig at the age of 9. He played Sharkboy in the kids' movie "The Adventures of Sharkboy and Lavagirl in 3-D" at 13.
Kirsten Dunst's career started at the age of 7, when she voiced the main character in the English version of the Japanese film "Kiki's Delivery Service." At 12, she was in "Interview with a vampire" and in 1995's "Jumanji," at 13.
Leonardo DiCaprio's first big role was in 1991, when he joined the cast of "Growing Pains" as Luke Bower at the age of 17. Before that, DiCaprio had been on the TV shows "Parenthood" and "Santa Barbara."
The Olsen twins, Mary-Kate and Ashley, weren't even a year old when they shared the role of Michelle Tanner on "Full House." From there, the twins, 13 in this photo, appeared in many films and had their own TV show, "Two of a Kind".
Lindsay Lohan's first big movie was as twins in 1998's "The Parent Trap," when Lohan was 12 years old. She then starred in a few Disney TV movies, including "Life-Size" and "Get a Clue," before starring in "Freaky Friday" when she was 17.
Sarah Jessica Parker, 15 in this photo, was starring on the TV show "Square Pegs" at the age of 17. Before that, she was on the 1980 TV show "3-2-1 Contact."
By the time Scarlett Johansson was 18, when this 2002 photo was taken, Johansson had been in several films, including "Home Alone 3" when she was 15.
Shia LaBeouf started acting when he was 12, doing small parts in various movies and TV shows before handing the role of Louis Stevens in the Disney series "Even Stevens" in 1999, when he was 13.
Diane Lane was 14 when she played Lauren King in 1979's "A Little Romance." She's photographed here with Francis Ford Coppola in 1984, after Lane had already appeared in 11 films and TV movies and shows.
Elijah Wood was 13 when he starred in 1994's "North". He played Huck Finn in 1993's "The Adventures of Huck Finn," and even appeared in "Back to the Future Part II" when he was 8, his first-ever screen credit.
By the time Jennifer Connelly was 20,she had starred in several movies, including 1985's "Phenomena",when she was 15 and 1986's "Labyrinth" when she was 16.
Jodie Foster was 14 when she played a 12 year old prostitute in the 1976 movie "Taxi Driver." Before that, Foster appeared in several TV shows, including "Paper Moon" at the age of 12.
Michelle Williams was 18 when she was cast in the popular teen drama series "Dawson's Creek." Before that, Williams appeared in a couple of TV movies and a handful of TV series, including "Step by Step" at 14.
Neil Patrick Harris sprang to stardom playing boy wonder Doogie Howser starting in 1989, when he was 16.
Rob Lowe, shown here at 19, got his start in 1979 at the age of 15 on the TV show "A New Kind of Family." He skyrocketed to fame during the 1980s as part of the Brat Pack, starring in "St. Elmo's Fire" and "About Last Night."