Christopher Lloyd will guest star on “The Big Bang Theory,” Variety has learned.

Details on his character and storyline are being kept under wraps, but the “Back to the Future” vet’s episode will air on Thursday, Dec. 1 at 8 p.m on CBS.

“We’re so excited to be working with Christopher Lloyd, and think we’ve created a fun part that fans will really enjoy,” said “The Big Bang Theory’s” executive producers in a statement.

In other “Big Bang Theory” news, earlier this week Variety reported that a spinoff series is in the works. The potential show, which is currently in early development, would focus on a young Sheldon Cooper, the character played by Jim Parsons on the flagship show. None of the current “Big Bang” cast members are expected to have on-camera roles in the spinoff, but Parsons is attached as an executive producer.

“The Big Bang Theory” is TV’s top comedy — a huge feat for a show in its 10th season. While the sitcom has yet to be renewed for another season, it’s expected that a pickup will come, as new deals for the high-paid actors are looming.