O'Brien isn't just marrying two random men, he'll be conducting the ceremony of a longtime staff member and his partner.
Gay marriage became legal in New York in July.
O'Brien may be making history for performing a gay marriage, but this isn't the first time a wedding has been part of a late-night talk show. Musician Tiny Tim married Miss Vicki on Johnny Carson's 'The Tonight Show' back in 1969.
'Conan' begins broadcasting from New York on Mon., Oct. 31 at 11PM ET on TBS. His shows will be taped at the Beacon Theater.
Tell us: Will you tune in to see Conan O'Brien perform a gay wedding?