The actor will appear at Amy (Mayim Bialik) and Sheldon's (Jim Parsons) wedding.

A central character from the Big Bang Theory prequel is growing up and moving to the flagship this season.

The Big Bang Theory has enlisted Jerry O'Connell to play Sheldon's (Jim Parsons) adult older brother Georgie, producers announced Wednesday night at PaleyFest in Los Angeles.

As Big Bang diehards know, Georgie is one of the central players in CBS' Young Sheldon, the prequel comedy from exec producers Chuck Lorre, Steve Molaro and Jim Parsons. O'Connell will take over the role currently played on Young Sheldon by Montana Jordan. The present-day version of Georgie will make his debut during a May episode for Sheldon and Amy's (Mayim Bialik) wedding.

Georgie won't be the only family member at Sheldon's wedding. Big Bang producers confirmed Wednesday that Georgie would be joined by his mother, Mary (Emmy winner Laurie Metcalf). "It was important for us," season 11 showrunner Steve Holland told fans packed into the Dolby Theatre at PaleyFest for the dual panel. And given Metcalf's busy schedule — she has a film and stage play in the works after earning an Oscar nom for Lady Bird and completing production on ABC's Roseanne revival — producers stressed that they made sure to lock the actress in early.

Producers also revealed that they plan to toy with a few pre-wedding traditions, including unconventional bachelor and bachelorette parties. "They don't go the way you think they would go," Kaley Cuoco (Penny) teased.

O'Connell, for his part, counts Burning Love, Crossing Jordan and CBS' The Defenders among his TV credits. He's repped by ICM Partners.