“The Big Bang Theory” Season 10 recently tapped actor Christopher Lloyd to guest star in an upcoming episode.

According to TV Line, Lloyd’s role is still being kept under wraps. His episode will air on Thursday, Dec. 1. According to the executive producers of the hit CBS TV show, they are also excited to work with Lloyd and are all pleased with the episode that he will be part of. When asked to share some details, the execs simply said, “We think we’ve created a fun part that fans will really enjoy.”

There are ongoing speculations that Lloyd’s character will be featured in a time travel sequence. If this were to be the case, Lloyd’s onscreen role may have something to do with Sheldon (Jim Parsons).

In the previous episodes, Sheldon has always been vocal about wanting to travel to the future. Some fans think that the character could be Sheldon’s counterpart when he’s much older. Others believe that he could be Sheldon’s grandfather in a dream sequence. As of late, Sheldon’s mom has already been introduced in the show, while his dad passed away years ago.

Unlike Sheldon, though, one character from the sitcom has a father, but hasn’t reunited with him in a very long time – Howard (Simon Helberg). While speaking with the same publication, executive producer Steve Molaro said that Howard and Bernadette (Melissa Rauch) having a baby soon can pave the way for the former to reunite with his dad. “Howard’s dad is certainly floating out there somewhere… I will tell you that we’ve been starting to think about other people we haven’t met, like Leonard’s dad and who that might be,” he said at that time. Leonard’s dad has already been introduced so Howard’s dad, Sam, could certainly be next.

“The Big Bang Theory” Season 10 airs Thursdays at 8 p.m. ET on CBS.