Johnny Galecki Leonard Hofstadter Actor Jim Parsons Sheldon Cooper Actor Kaley Cuoco Penny Actor Simon Helberg Howard Wolowitz Actor Kunal Nayyar Raj Koothrappali Actor Mayim Bialik Amy Farrah Fowler Actor Melissa Rauch Bernadette Rostenkowski Actor Stephen Hawking Stephen Hawking Guest Star John Ross Bowie Barry Kripke Guest Star Brian Posehn Bert Kibbler Guest Star Kunal Dudheker Guest Star Chuck Lorre Executive Producer, Writer Bill Prady Executive Producer Steven Molaro Executive Producer Erik Kaplan Writer Maria Ferrari Writer Steve Holland Writer Jim Reynolds Writer Jeremy Howe Writer Mark Cendrowski Director