O'Brien was in New York to do some shows from the Beacon Theatre
Conan O’Brien returned to his old stomping grounds at NBC – but just for a visit.
Following a less than 1-year stint as host of The Tonight Show, Conan was bumped off the program, only to be replaced by Jay Leno.
But while he was in NYC to do some shows from the Beacon Theatre, Conan surprised Jimmy Fallon, who tapes his late night show in the same studio Conan used to work from.