"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.
— Emily Zemler (@emilyzemler) July 19, 2013
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.
— CodyBranom (@CR_Branom) July 19, 2013
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: