Bob Newhart is heading to "The Big Bang Theory" to give Sheldon and the gang a science lesson.
According to TVLine, the "Bob Newhart Show" and "Newhart" star is stopping by "The Big Bang Theory" play Professor Proton, the former host of Sheldon's (Jim Parsons) favorite childhood science show.
The episode, set to air May 2, will center on Sheldon's online search for his favorite TV host, played by Newhart. Once he tracks Professor Proton down, Sheldon discovers he can be booked for events and invites him to his house.
Newhart's "Big Bang Theory" stint is one of his few TV appearances in recent years. The six-time Emmy winner was seen on "ER" in 2003, "Desperate Housewives" in 2005 and "NCIS" in 2011.
Despite Sheldon's excitement about Professor Proton, it's not unlikely that he'll offend him. In a January episode of the series, he managed to tick off someone in the Human Resources department, played by guest star Regina King.
"All women are slaves to their biological urges, ya know?" Sheldon explained after getting himself into a sticky situation with his assistant Alex (Margo Harshman) and Leonard (Johnny Galecki). "Even you. You’re a slave," he said.
"The Big Bang Theory" airs Thursdays, 8 p.m ET on CBS.
CORRECTION: This post previously did not include Newhart's "NCIS" appearance.