'Big Bang Theory' Enlists Kal Penn, Sean Astin

Kal Penn - Sean Astin-Split-Getty-H 2018
Jamie McCarthy/Getty Images; JB Lacroix/WireImage

Sheldon and Amy are headed for a major highlight on CBS' The Big Bang Theory.

Kal Penn (Designated Survivor) and Sean Astin (Goonies) have been tapped to guest-star in an upcoming episode of the final season of the Chuck Lorre and Bill Prady comedy.

Penn and Astin will play Dr. Campbell and Dr. Pemberton, respectively, a team of physicists who accidentally confirm Sheldon and Amy’s super-asymmetry theory. An airdate for the episode has not yet been determined.

Their casting helps cement a key final season plot detail — that newlyweds Sheldon (Jim Parsons) and Amy (Mayim Bialik) have indeed made a scientific breakthrough that could dramatically alter their careers (and personal life). For the past season-plus, the couple have been working diligently on their super-asymmetry theory after altering their discovery after initially being proven wrong.

The news arrives as Big Bang Theory, TV's No. 1 comedy among total viewers, is poised to wrap its 12-season run in May.

Penn next reprises his role in ABC turned Netflix drama Designated Survivor. His credits include House, How I Met Your Mother and the Harold and Kumar franchise. He's repped by UTA, Industry Entertainment and Fuller Law.

Astin, meanwhile, starred in season two of Netflix hit Stranger Things and counts The Lord of the Rings trilogy and more among his credits. He's with Abrams Artist Agency, Luber/Roklin and Bloom Hergott.

Big Bang Theory airs Thursdays at 8 p.m. on CBS.