07/19/2013 03:20 pm ET Updated Jul 19, 2013

Johnny Galecki Surprises 'Big Bang Theory' Comic-Con Panel In 'Star Wars' Costume (PHOTOS)


"Big Bang Theory" star Johnny Galecki surprised fans at the show's Comic-Con panel Friday, donning a Boushh "Star Wars" costume to pose as a fan asking a question.

It was the third surprise of the session, after Melissa Rauch, who plays Bernadette on the hit CBS comedy, was revealed as the surprise moderator.

But that wasn't it. The panel kicked off with a recorded video message from Stephen Hawking, the theoretical physicist and noted "Big Bang Theory" fan, who has also appeared on the show.

They also played a "Big Bang Theory" Season 6 highlight reel, which you can watch below:

'The Big Bang Theory'