When she was 13, Jessica Alba appeared on the Nickelodeon comedy series “The Secret World of Alex Mack.”
Britney Spears appeared on “The Mickey Mouse Club” in 1992.
Leonardo DiCaprio appeared on “Romper Room” when he was only five years old. He was reportedly asked to leave the set for being too disruptive. He also appeared on multiple seasons of Growing Pains.”
Miley Cyrus got her start on the Disney program “Hannah Montana, on which she appeared from 2006-2011.
Ben Affleck appeared on the PBS kids series “The Voyage of the Mimi” when he was a child.
Selena Gomez appeared on the children’s program “Barney and Friends” from 2002-2004.
Jennifer Love Hewitt appeared in the Disney kid’s show “Kids Incorporated” from 1989-1991.
Ryan Gosling appeared on “The Mickey Mouse Club” from 1993-1995. He also appeared on “Are You Afraid of the Dark? “ (1995), “Goosebumps “ (1996), and “Breaker High “ (1997–98).
Keri Russell appeared on “The Mickey Mouse Club” from 1991-1994.
Shia LaBeouf appeared on The Disney Channel show “Even Stevens” in the early 2000s. He earned a Daytime Emmy Award for the performance.
Alanis Morisette appeared five episodes on the popular Nickelodeon program “You Can’t Do That on Television when she was in elementary school.
Justin Timberlake appeared on “The Mickey Mouse Club” from 1993-1994.
Demi Lovato appeared on “Barney & Friends alongside Selena Gomez.
Annette Funicello appeared on “The Mickey Mouse Club” from 1955-1959.
Julia Stiles appeared on “Ghostwriter” from 1993-1994.
Alan Arkin appeared in several episodes of “Sesame Street “ from 1970-1971.
Christina Aguilera appeared on “The Mickey Mouse Club” from 1993-1994.
Hayden Christensen appeared in an episode of “Goosebumps ” in 1997.
Fergie appeared on The Disney Channel show “Kids Incorporated” from 1984-1989. She also provided the voice of Sally in two made-for-television “Peanuts cartoons.
Kenan Thompson appeared on “All That,” “Kenan & Kel ” and he was a reporter for CNN’s ” Real News for Kids.“
Amanda Bynes appeared on the Nickelodeon sketch comedy show “All That,” which ran from 1994-2005.
Raul Julia appeared in four episodes of “Sesame Street” in the early-70s.
Michelle Trachtenberg appeared on the Nickelodeon series “The Adventures of Pete & Pete” from 1994-1996.
Nick Cannon appeared on the Nickelodeon sketch comedy show “All That as a teen.
Audiences first fell in love with Hilary Duff as the adorable title character on the Disney show “Lizzie McGuire” from 2001-2004.
Jewel Staite appeared in several episodes of “Are You Afraid of the Dark? “
Joanna Garcia appeared in “Are You Afraid of the Dark? “ from 1994-1996 as well as an episode of “Clarissa Explains It All.”
Penn Dayton Badgley appeared in a couple of episodes of the Nickelodeon show “The Brothers García.”
Comedian Gabriel iglesias appeared in season six of the Nickelodeon sketch comedy series “All That,” in 2000.
Felicity Jones briefly appeared in “The Worst Witch ” when she was a tween.
Holly Robinson Peete appeared on the first episode of “Sesame Street” in 1969.
Taran Killam appeared on Nickelodeon’s “The Amanda Show .”
Comedian Kel Mitchell appeared on the Nickelodeon sketch comedy show “All That” and the spin-off “Kenan and Kel.
Jan-Michael Vincent appeared in “The Banana Splits “ from 1968-1969.