Ferrell, of course, was the first guest on "The Tonight Show With Conan O'Brien" when the show launched June 1. It has become somewhat of a tradition on "Tonight."
Jay Leno's first guest on the show, Billy Crystal, guested on what was supposed to be the talk show host's second-to-last "Tonight" in May. (Leno is now set to return as "Tonight" host March 1.)
The reason why Crystal didn't appear on the very last episode was that, in a demonstration of what was billed as a seamless transition, Leno's guest then was Conan O'Brien.
It is safe to say that there is zero chance O'Brien would return the favor.
Other big names scheduled for O'Brien's final week on "Tonight":
Wednesday, Jan. 20: Adam Sandler, Joel McHale and musical guest Joss Stone
Thursday, Jan. 21: Robin Williams and musical guest Barry Manilow
Friday, Jan. 22: Tom Hanks, Ferrell
As for the official announcement of O'Brien's exit and Leno's return to "Tonight," it was delayed again Tuesday as the two sides have not settled yet on the size of the severance packages of the "Tonight" staff.
– Nielsen Business Media