Johnny Galecki Leonard Actor Jim Parsons Sheldon Actor Kaley Cuoco Penny Actor Simon Helberg Wolowitz Actor Kunal Nayyar Koothrappali Actor Melissa Rauch Bernadette Guest Star Carol Ann Susi Debbie Wolowitz Guest Voice Aarti Mann Priya Koothrappali Guest Star Phil Abrams Dr. Bernstein Guest Star Sharon Omi Nurse in Biohazard Suit Guest Star Chuck Lorre Executive Producer, Writer Bill Prady Executive Producer, Writer Eric Kaplan Writer Jim Reynolds Writer Steven Molaro Writer Steve Holland Writer Howard Murray Director