New promo photos have been released from this week’s episode of The Big Bang Theory, giving center stage to an exciting guest star and a few fuzzy friends. Mild spoilers ahead.

This week’s upcoming episode of The Big Bang Theory is set to be a big one. “The Proton Resurgence” will feature none other than television legend Bob Newhart (of The Bob Newhart Show, Newhart, and many other classic shows) as the venerable Professor Proton himself. In addition to the first still photo released from the episode, an early sneak peek clip was released last week. Check out the complete set of professor-y still photos from “The Proton Resurgence” right here:

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We can’t decide which is more adorable – Sheldon’s excitement (totally palpable even through the stills), or the sight of Bob Newhart playing with a puppet. (And how sweet is that last curtain-call shot? The whole cast looks like they’re having a blast.) With apologies to Raj’s admittedly-cute dog/life companion, it looks like she won’t hold a candle to the homo sapiens this week… though judging by the official summary for “The Proton Resurgence,” Raj’s (other) best friend may be giving Bernadette and Howard a run for their money:

Sheldon and Leonard hire Professor Proton, the host of their favorite childhood TV show, to perform. Also, Howard and Bernadette run into trouble babysitting Raj’s dog.

The Big Bang Theory airs Thursdays at 8 p.m. on CBS.

Are you excited to see Bob Newhart on ‘The Big Bang Theory’?