Take It Back and See the Cast of The Big Bang Theory Before They Were Stars

Nearly ten years ago, The Big Bang Theory made its debut. Starring Johnny Galecki, Jim Parsons, and Kaley Cuoco, among others, the CBS sitcom has picked up nine Emmys over its 10-season run and topped viewer ratings. See the cast of the show before they were stars, ahead.

Big Bang Theory fans know Jim Parsons as Sheldon Cooper, a role he took on early in his career. Pictured here in 2004, Parsons made his on-screen debut in one episode of Ed in 2002. He went on to appear in TV movies and pop up as Tim in Garden State soon after.

Pictured here in 1990, Johnny Galecki started acting at the age of 12. The future star, who plays The Big Bang Theory's Leonard Hofstadter, earned his first on-screen credits in the '80s in TV movies, A Night in the Life of Jimmy Reardon, Prancer, and National Lampoon's Christmas Vacation.

Kaley Cuoco first picked up an acting gig when she was just 7 years old, appearing in the 1992 thriller Quicksand: No Escape. Pictured here in 2002, Cuoco found success on the small screen, doing a stint on Ladies Man before booking her breakout role in 8 Simple Rules.

Fans have known Mayim Bialik since she was a child star. The actress, who plays Amy Farrah Fowler on The Big Bang Theory, appeared in episodes of The Facts of Life, Webster, and MacGyver before leading Blossom as Blossom Russo.

Months before he joined The Big Bang Theory as Raj Koothrappali, Kunal Nayyar made his small-screen debut in one 2007 episode of NCIS, pictured here.

Pictured here with Herve Villechaize in 1982, Simon Helberg started acting in the 1990s. He made his on-screen debut in Mumford before hitting the small screen in episodes of Popular, Undeclared, and Sabrina, the Teenage Witch.

Melissa Rauch found her spot on The Big Bang Theory as Bernadette Rostenkowski. Pictured here in 2006, the actress earned her first on-screen credit the same year, appearing in the film Delirious.