Bob Newhart is coming back to “The Big Bang Theory,” Variety has learned. The comedic icon will guest star on the Dec. 17 episode this season.

The upcoming guest shot will mark Newhart’s fourth time appearing on the CBS sitcom.

Newhart will reprise his role as Arthur Jeffries, Sheldon’s (Jim Parsons) childhood hero. Though the episode has not filmed yet, Arthur returns as a ghostly Jedi in Sheldon’s dreams to help him sort out his feelings and make a very important decision.

First guest starring during the sixth season in 2013, Newhart also appeared in two episodes during the seventh season. For his first appearance on the show, Newhart earned an Emmy award.

“The Big Bang Theory” marks a reunion for Newhart and CBS, which was home to both of his hugely successful series “The Bob Newhart Show,” which ran from 1972-1978 and “Newhart,” which was on the network from 1982-1990.

“The Big Bang Theory” is currently in its ninth season, airing Thursdays at 8:00 p.m.