David Letterman and Conan O'Brien Poke Fun at Rival Jay Leno

Yahoo! TV

For the first time in 13 years, Conan O'Brien appeared as a guest on David Letterman's show Thursday night and it didn't take long for the two comedians to start talking about Jay Leno. In fact, it was the first topic of the night and the conversation lasted until the commercial break, complete with head-shaking, finger-pointing impressions of the "The Tonight Show" host.

Two years after the big "Tonight Show" shakeup, O'Brien took a seat next to "The Late Show with David Letterman" host, who has had his own feud with Leno over the years despite appearing in a Super Bowl ad together in 2010, and the men sat in silence for a brief period, pretending they had nothing to talk about. Letterman broke the ice, quipping: "The longer we just sit here, the more uncomfortable it will make Jay." That was all O'Brien needed, quickly launching into a Jay impression: "You know Jay's watching right now. He's getting a live feed in a satellite truck right now. He is watching every second. 'Dave looks unhappy. He's going to pack it in soon.'" When Letterman did his own Jay imitation, O'Brien scolded him, "You're not doing the head waggle." Letterman replied: "It gives me an inner ear problem."

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Speaking more in-depth about Leno reclaiming his "Tonight Show" hosting gig just months after O'Brien replaced him, Letterman told O'Brien he was "delighted" by the whole situation because it reminded him of the Leno he knows. "I've know Jay a long, long time," Letterman said. "We go back to the mid-'70s… Jay was always 'the guy.' He was the funniest guy. He was the guy you'd go to see. He was the guy you wish you could be more like. He was funny. He was also a bit of a brat. When this came along I said: 'Oh, yes, this is the Jay I know.'"

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When asked if he had a friendship with Leno prior to the drama, O'Brien said nothing more than an occasional phone call – then threw in a jab about the notorious classic car lover. "He and I are different, so we didn't have a lot to talk about in common," O'Brien said. "I didn't own many automobiles that were made before 1904, primarily of brass and leather… There are very few ways in which he and I relate. We're not interested in the same things. He was my lead-in. He was the host of 'The Tonight Show.' I was the host of 'The Late Night Show.'"

O'Brien said he's happy to have left the NBC fiasco behind for his new cable series, "Conan." "I'm very lucky to get to go on television," he told Letterman. "TBS lets me do whatever I want. They don't watch it. They don't care. Checks come in. We took all of our people with us. Everybody is happy, so I'm thrilled. It worked out."