As The Big Bang Theory makes its way through what is going to be its final season, it’s a great opportunity to bring back some old friends. With that in mind, for Jim Parson’s Sheldon Cooper there could be nobody better than the late Professor Proton, hence the return of Bob Newhart playing the character as a part of Sheldon’s imagination.

“When Jim has a problem,” the 89-year-old veteran comedian explains to Entertainment Tonight, “he comes to me. He and Amy had a fight and he came to me and wanted my advice on how to handle their first fight.”

In the same interview, Jim Parsons adds, “Bob’s back to offer advice because when you have marital problems, you go to Bob Newhart in Jedi robes.”

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(Photo Credit: CBS)

Speaking to the Television Academy, Bob explains that when he was first approached to appear on The Big Bang Theory by series co-creator Chuck Lorre, he had a few ground rules that he needed to be accepted.

He remembers, “I told him I loved the writing on the show and I loved the cast. I said I wanted it to be more than one shot, so we made it a three-shot, which became a four-shot, and it’s gone on from there. I also said it had to be filmed in front of a live audience, and he said, ‘Yeah, that’s what we do.’ So it’s a joy. I didn’t have my fastball, but I had maybe, like, a changeup, you know? I still have it, and I wanted to work.”

Here’s how CBS describes the episode — titled “The Planetarium Collision” — which airs the night of Thursday, Oct. 18, “When Amy doesn’t have time to work on super-asymmetry, Sheldon goes to great lengths to ensure she’s available to work with him, even it if means accidentally sabotaging her career in the process. Also, Koothrappali doesn’t want Wolowitz to join him in hosting a show at the planetarium.”

His “great lengths” obviously lead to a return encounter with Professor Proton (aka Arthur Jeffries).