The Big Bang Theory Scene That Made Bob Newhart Break Down In Tears

A whole bunch of iconic performers appeared on "The Big Bang Theory" throughout its twelve-season run; hell, the list of "Star Trek" veterans who popped up on Chuck Lorre's sitcom is a pretty hefty list all by itself. Most of the time, people like William Shatner or James Earl Jones simply played larger-than-life versions of themselves, but sometimes TV legends would show up to have a little fun ... like Bob Newhart, who was a repeat guest star on "The Big Bang Theory" as Sheldon Cooper's (Jim Parsons) childhood idol Professor Proton, also known as Arthur Jeffries.

Apparently, Newhart's first day on the set of "The Big Bang Theory" was seriously emotional for everyone involved ... especially Newhart himself, who found himself totally overwhelmed by the live audience's effusive reaction. As Jim Parsons told Parade, tears were shed.

"The night we taped the first scene he ever did with us, he appeared in the hallway and the show stopped — just completely stopped — from the standing ovation the live audience gave him," Parsons revealed, before saying he was really taken aback at the mere prospect of performing next to such a huge comedy star. "He cried. I think we all cried. It was profound, and I realized how much I'd been stuffing down my knowledge of how profound it was to work with Bob all week at rehearsal, because who the hell can do good work while saying, 'I can't f**king believe I'm working with Bob Newhart!' in your head the whole time? No one. But the dam broke in that moment."

Armed with the catchphrase "There is no problem you can't solve if you use your noggin," Professor Proton — whose real name is Arthur Jeffries — first appears in season 6 of "The Big Bang Theory" in the 22nd episode, "The Proton Resurgence." When Sheldon and his best friend Leonard Hofstadter (Johnny Galecki) discover that the good professor is alive and available for children's birthday parties, Sheldon wants to book him for no occasion in particular; using Leonard's email, he convinces Arthur to visit them at their apartment. After a sleepless night — for Sheldon, who is simply too excited to get any rest — Arthur arrives but ends up stranded on their staircase thanks to the apartment building's perpetually broken elevator. 

Arthur — who is understandably alarmed by Sheldon's devoted attention — ends up telling Penny (Kaley Cuoco) that it's hard for him to get work as a real scientist after years of playing "Professor Proton," so he's forced to do birthday parties for kids (who, apparently, bite him a lot). Naturally, Sheldon is so overwhelming that Arthur ends up going to the hospital (accompanied by his biggest fan), but the two become friends after Sheldon sings his childhood lullaby "Soft Kitty" to Arthur. Newhart ended up reprising his role in six episodes of the show, including one in its twelfth and final season.

Bob Newhart's final performance on "The Big Bang Theory" envisioned him as a Jedi spirit on the fictional "Star Wars" planet Dagobah — during season 12, which aired in 2017 — advising Sheldon on how to comfort his wife Amy Farrah Fowler (Mayim Bialik). It's an oddly touching scene and a perfect final outing for Newhart, who also appeared on the show's first spin-off "Young Sheldon" across three episodes as Professor Proton. In 2024, when Newhart passed away at 94 years old after suffering a few brief illnesses, "Young Sheldon" and "Big Bang Theory" showrunner Chuck Lorre said some extremely kind words about working with Newhart ... and shared a story about the guest star.

In a statement provided to Deadline, Lorre said, "For years I begged Bob to appear on one of my shows. He always said no. But then he fell in love with 'The Big Bang Theory' and said yes – with two provisions. One: his character had to have an arc that spanned several episodes. And two: he wanted to win an Emmy. We delivered on both. I got to work with a comedy legend. A master of the craft, and a kind and gentle man. I even got to call him a friend. How lucky am I?" It is sort of amazing (and not necessarily in a good way) that Newhart, who was nominated for multiple Emmys for his eponymous shows "The Bob Newhart Show" and "Newhart," only won one for "The Big Bang Theory," but at least he accomplished that career goal thanks to the show.

"The Big Bang Theory," including Newhart's episodes, is streaming on Max now.