Start Slideshow 3. Jamie Lynn Spears Here's another All That kid: Britney's lil sis and was on the show from 2002-2004. Then, she was given the lead role in Zoey 101 in 2005. The show ran for four seasons before going off the air, mostly because she had a baby.JLS launched her country music career at the end of 2013 with her single "How Could I Want More." She's currently finishing up her debut album and planning her wedding. 5. Emma Roberts Aside from being Julia Roberts' niece, got her start in showbiz thanks to Unfabulous in 2004.After the show ended in 2007, she mainly starred in movies before returning to the tube last year in American Horror Story: Coven. She's now engaged to her co-star Evan Peters. Start Slideshow 6. Jennette McCurdy This blond has spent almost a decade on Nickelodeon. got her start on an episode of Zoey 101 back in 2005 and has since appeared on tons of Nick shows. She had a lead role on iCarly and started on the spin-off Sam & Cat in 2013, alongside Ariana Grande Start Slideshow 7. Ariana GrandeYou may know best for her catchy tunes these days, but she got her start in the spotlight on Nick. She started playing Cat Valentine on Victorious in 2010 and is now on her own show Cat & Sam.We'll see how long she sticks around on Nick now that she's had a single on the Billboard Hot 100 Start Slideshow 8. Amanda Bynes was a Nick kid through and through. She, too, started off on All That, then got her own place in the spotlight with The Amanda Show in 1999.After leaving Nickelodeon, Bynes starred in a few TV shows and movies, though her last acting role was in 2010's Easy A. After some mental health issues in 2013, the former actress is apparently not enrolled in fashion school. Start Slideshow 9. Jessica Alba was cast in 3 episodes of the SNICK show The Secret World of Alex Mack in 1994. It didn't exactly put her on the map, but her early acting work surely laid the foundation for her Dark Angel days.Obviously Alba is currently one of the biggest stars in Hollywood. She's also mom of two and married to Cash Warren. Start Slideshow 10. Melissa Joan Hart said what all the tween girls were thinking about boys, pimples, and annoying siblings while she starred in Clarissa Explains It All from 1991 to 1994. From there, she found success as Sabrina the Teenage Witch. After a long break from the sitcom world, she returned to the tube with Melissa & Joey in 2010. Start Slideshow 13. Miranda Cosgrove has grown up on Nick over the last few years. She came on the Nick scene as an 11-year-old in Drake & Josh from 2003-2007, then starred on her own show, iCarly, from 2007 to 2012. Now she's 20, if you can believe that.Cosgrove will next star in the NBC pilot Girlfriend in a Coma. She was also the voice of Margo in both Despicable Me movies.
14. Christine Taylor played Nickelodeon's cutest cowgirl on Hey Dude from 1989-1991.She went on to marry Ben Stiller and has appeared with him in almost everything he's been in since — Zoolander, Dodgeball, Tropic Thunder, Curb Your Enthusiasm, and more. Start Slideshow 17. Michelle Trachtenberg at the age of 9, landed her first credited film role (she'd already been in a slew of TV commercials) as Nona F. Mecklenberg in Nick's The Adventures of Pete & Pete. At the same time, she was starring on All My Children, where she met future Buffy co-star Sarah Michelle Gellar.Since her Nick days, she's starred on shows like Gossip Girl and Weeds and will star in The Scribbler on the big screen in 2014