The British cosmologist has frequently been name-checked by the show's scientist characters, and now the lovable losers are set to meet their hero.
Producer Bill Prady says, "When people would ask us who a 'dream guest star' for the show would be, we would always joke and say Stephen Hawking - knowing that it was a long shot of astronomical proportions. In fact, we’re not exactly sure how we got him. It’s the kind of mystery that could only be understood by, say, a Stephen Hawking."
Hawking's casting comes just weeks after Star Trek legend Leonard Nimoy made a special appearance, much to the delight of the show's nerds.