No storyline details are being shared, but CBS has revealed that Young Sheldon‘s Iain Armitage, Lance Barber and Montana Jordan will appear in an upcoming episode of mothership series The Big Bang Theory. Armitage’s Sheldon, Barber’s George and Jordan’s Georgie will make cameos in an episode that will air in December as their Young Sheldon characters, according to CBS.

Young Sheldon co-creator Steve Molaro, speaking at Deadline’s Emmy Contenders last April, said “There’s no reason why we can’t keep going back and forth in this weird time portal that has been created between the two shows,” when it comes to the number of crossover episodes between CBS’s Young Sheldon and its predecessor, The Big Bang Theory. Because of the time difference between the two shows (they are set nearly three decades apart), tie-ins are difficult given the age differences.

The Big Bang Theory is executive produced by Chuck Lorre, Bill Prady, Steven Molaro and Steve Holland. The series stars Johnny Galecki, Jim Parsons, Kaley Cuoco, Simon Helberg, Kunal Nayyar, Mayim Bialik and Melissa Rauch. The Big Bang Theory is produced by Chuck Lorre Productions, Inc., in association with Warner Bros. Television.

Young Sheldon is executive produced by Chuck Lorre, Steven Molaro, Jim Parsons and Todd Spiewak. The series is produced by Chuck Lorre Productions, Inc. in association with Warner Bros. Television.

The Big Bang Theory airs Thursdays at 8 PM, followed by Young Sheldon at 8:30 PM on CBS.