Jan. 3 (UPI) -- Sean Astin and Kal Penn are set to guest-star on an upcoming episode of The Big Bang Theory which is currently in its 12th and final season.
Astin and Penn will be portraying Dr. Pemberton and Dr. Campbell, respectively, physicists who accidentally confirm newlyweds Sheldon (Jim Parsons) and Amy's (Mayim Bialik) super-asymmetry theory.