Conan O'Brien Returns to His Old 'Late Night' Studio in New York (Video)

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Conan O'Brien

Conan O'Brien returned to his old stomping grounds last night on NBC's Late Night With Jimmy Fallon -- and he reunited with an old friend.

O'Brien, who left NBC last year after less than 12 months as Tonight Show host, dropped by Jimmy Fallon's late-night show, who films in his old studio in New York City. He will be in town doing some shows from the Beacon Theater.

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Fallon was discussing the fall weather, when O'Brien made a surprise appearance. "How you doin'?," O'Brien said to Fallon, who said, "This is unbelievable."

"I was back in New York and I wanted to check out my old studio. Hey Max!" O'Brien joked, pointing to Questlove, drummer for The Roots. "Hair looks amazing, man." (He was referring to his Late Night/Tonight Show counterpart, Max Weinberg, who is not on TBS' Conan.)

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"You were here for 16 years. Then ... what happened?," Fallon asked. The two began to laugh. "Don't you worry about, you're a young guy," O'Brien joked.

"I left something here, something important to me. ... I think I'm going to need it again," he said, before revealing Triumph the Insult Comic Dog.

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Watch the rest of O'Brien's appearance on Late Night below: