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.
The theory is a scientific breakthrough that could change the lives of Sheldon and Amy. An airdate for the episode has yet to be announced.
The Big Bang Theory's 12th and final season airs Thursdays at 8 p.m. on CBS. The comedy is set to conclude in May.
Astin, best known for starring in The Lord of the Rings trilogy and who appeared in Season 2 of Stranger Things, is set to star opposite Melissa Joan Hart in Netflix comedy series, No Good Nick.
Penn, of Harold and Kumar fame, will next be reprising his role on Designated Survivor which is moving from ABC to Netflix.