CBS almost fired a main cast member of . The long-running sitcom had some difficulties getting off the ground, and initially, the original  pilot only featured Sheldon and Leonard with an entirely different cast. But, after it was sent back for some re-writes, producers Chuck Lorre and Bill Prady decided to add Kaley Cuoco as Penny, Simon Helberg as Howard, and Kunal Nayyar as Raj. A couple of seasons later, Melissa Rauch's Bernadette and Mayim Bialik's Amy rounded up the core cast of .