It's Bob Newhart on The Big Bang Theory! This is a photo from "The Proton Displacement."
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Dr. Proton and Bill Nye the Science Guy both visit The Big Bang Theory. "The Proton Displacement" is the seventh episode of the show's seventh season.
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The Big Bang Theory Season 7 Episode 7 Quotes

Sheldon: No, go ahead, say it. I know what it is. I've heard it my whole life. The word's "annoying." Go ahead, say it. Say it. Say I'm annoying.
Amy: Sheldon...
Sheldon: Oh, it won't hurt my feelings. Go ahead, Amy, say I'm annoying. I'm annoying. I'm annoying. I'm annoying.

Dr. Jeffries: Hold on. You ... you have a girlfriend?
Amy: Hey look -- we're wearing the same orthopedic shoes. I can't believe I dress like a celebrity.
Dr. Jeffries: O-Okay, I get it now.