Bob Newhart, an established television star, joined the cast of The Big Bang Theory as Professor Proton. He insisted on filming his scenes live with a studio audience and wanted to be a recurring character. Despite concerns about the audience recognizing him, Newhart received a warm reception. He found similarities between the set of The Big Bang Theory and his previous shows, but noted differences in comedic timing due to changes in audience preferences. Newhart believed that today's young audience wants quick jokes and immediate gratification.