Bob Newhart to guest star on 'Big Bang Theory'

Legendary actor Bob Newhart will lend his comedic chops to an upcoming episode of CBS' massive hit, "The Big Bang Theory," TVLine reported Thursday.

The former "Bob Newhart Show" and "Newhart" star will play the host of Sheldon's favorite childhood show, the Bill Nye-esque Professor Proton.

In the May 2 episode, Sheldon discovers that his childhood hero is available for parties and events.

Professor Proton is Newhart's first guest role since he appeared on NCIS in 2011. The six-time Emmy nominee also played Morty Flickman during a three-episode stint on "Desperate Housewives" in 2005.