Johnny Galecki Leonard Actor Jim Parsons Sheldon Actor Kaley Cuoco Penny Actor Simon Helberg Wolowitz Actor Kunal Nayyar Koothrappali Actor Mayim Bialik Amy Actor Melissa Rauch Bernadette Actor Kevin Sussman Stuart Guest Star Marcus Folmar Security Guard Guest Star Lexie Contursi Beautiful Young Woman Guest Star Chuck Lorre Executive Producer Bill Prady Executive Producer Steven Molaro Executive Producer David Goetsch Writer Jim Reynolds Writer Tara Hernandez Writer Steve Molaro Writer Steve Holland Writer Maria Ferrari Writer Mark Cendrowski Director