Big Bang Theory Season 9
The Big Bang Theory's 200th episode will feature Sheldon's birthdayCBS

The Big Bang Theory's 200th episode titled The Celebration Experimentation airs this Thursday (25 February) at 8pm EST on CBS. Episode 17 of season 9 will be a special event with Batman actor Adam West guest-starring as himself.

Click here to watch the episode via live stream online on CBS All Access. You can also click here to watch it online (only in the US).

The episode will find Amy, Leonard, Penny and the rest of the gang throwing a birthday bash for Sheldon. Fans know that Dr Cooper is not a fan big of surprise parties but at Amy's request, he will make an exception this year. Other than the Batman actor, the episode will also bring several familiar faces, including Wil Wheaton as himself, Christine Baranski as Leonard's mother Beverly and Sara Gilbert as Leslie Winkle.

Creators Steve Molaro, Chuck Lorre and actor Jim Parsons spoke about the special episode in an interview with TV Insider. "We've been kicking around getting Adam West for a while." Molaro said. "We tried it last year and it didn't quite work out, but we finally got it and he's incredible. He is funny, lovely and hilarious every moment he's on the screen."

Speaking about Sheldon's predicament, Parsons said: "He is so freaked out by having a bunch of people there to admire him. That really upsets him and sets him off in a weird way where he doesn't know how to deal with it. I was surprised, and the writers are always doing something with this character that I don't expect, which has made it so enjoyable."

Co-creator and executive producer Lorre said: "The cast is a remarkable ensemble and I've never seen anything like it. Added to that is a staff of comedy writers who truly love and care about the show. It's not just a job and nobody is phoning it in. Nine years later, everybody is deeply committed to making each episode the best episode we can do."