Conan O'Brien, David Letterman

Conan O'Brien is heading to Late Night with David Letterman for the first time in 13 years.

It should be an interesting sit-down, to say the least. The two have a lengthy history, as O'Brien took over Letterman's Late Night spot in 1993. They also have a shared history involving fellow late night host Jay Leno. In 1992, Leno was hired to take over The Tonight Show from Johnny Carson — a gig Letterman had been vying for and the catalyst for Letterman's exit from NBC.

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O'Brien and Leno had their own dustup in 2010, when just seven months after taking over The Tonight Show from Leno, O'Brien was asked move his ratings-challenged Tonight Show in order to give Leno's new show the 11:35/10:35c timeslot. O'Brien left NBC, and Leno was reinstated as Tonight Show Host. O'Brien now hosts Conan, a talk show on TBS.

This will mark Conan's fifth time as a guest on Letterman's show. He last appeared in January 1999.

Conan's appearance on Late Night with David Letterman airs Thursday, May 17 at 11:35/10:35c.