Bob Newhart was Conan O’Brien’s late-night guest on Monday, celebrating the 45th anniversary of The Bob Newhart Show.

In the course of their conversation, Newhart talked about his introduction to Don Rickles, as well as another comic who stole his material, the glaring error in The Bob Newhart Show‘s opening credits, and how ineffective his Dr. Hartley was as a therapist.

Newhart and Conan have known each other a long time; Newhart having starred in a memorable running gag when Conan hosted the 2006 Emmy Awards. Introducing “beloved TV icon Bob Newhart,” who was locked in an airtight capsule with just three hours worth of air, Conan warned Emmy nominees that if their acceptance speeches run long, “Bob Newhart dies.” Conan repeated the warning throughout the broadcast, Newhart looked increasingly concerned, and the Emmys came in at 3 hours that year.

Conan will host a conversation with Newhart about The Bob Newhart Show, Tuesday night at the TV Academy.