The hit sitcom premiered on CBS on Sept. 24, 2007, with a core cast of five actors: Jim Parsons, Johnny Galecki, Kaley Cuoco, Simon Helberg and Kunal Nayyar. By season 4, the ensemble grew when Mayim Bialik and Melissa Rauch were promoted to full-time series regulars.

'Stuart Fails to Save the Universe' is a wildly different series from 'The Big Bang Theory' and its prequels, elevating Kevin Sussman, Brian Posehn, Lauren Lapkus and John Ross Bowie to leads.

Bernadette Rostenkowski wearing glasses on The Big Bang Theory (2007-2019) - CBS Successfully introducing new characters to a popular sitcom can be challenging, but "The Big Bang Theory" is notorious for doing so on several occasions, with Melissa Rauch ...

Despite earning millions of dollars from playing Sheldon Cooper on The Big Bang Theory, Jim Parsons admitted he was 'not happy' and 'stressed' during that period