A new video has been released of executive producer Steve Molaro explaining how the Star Wars Day episode of The Big Bang Theory came together.

“Lucasfilm said ‘if you guys ever want to do anything, we love you’re show, we’re happy to help. Let us know,’ said Molaro. “So we thought that was really cool. So that was floating around in the back of heads, and we knew we wanted to bring Bob [Newhart] back. And this idea happened where we could blend the two. And Bob, Professor Proton, would die and come back as Sheldon’s Obi-wan.”

The Star Wars Day episode of The Big Bang Theory, “The Proton Transmogrification,” aired last night.

The Big Bang Theory airs Thursday nights on CBS.