''The Proton Displacement'' -- Sheldon feels slighted when Professor Proton (Bob Newhart, right) seeks advice from Leonard (Johnny Galecki, center) instead of him, and he seeks revenge by befriending a rival science TV host, Bill Nye (left), on THE BIG BA Photo

From: Photo Flash: First Look at Bob Newhart's Return to THE BIG BANG THEORY

Bob Newhart makes his return to CBS' THE BIG BANG THEORY on the upcoming episode titled 'The Proton Displacement' - check out a first look below!