Two days after NBC announced a strong guest list for the first two weeks of Jay Leno's return to the Tonight show, CBS revealed an equally strong lineup for next week's Late Show with David Letterman. It includes Matt Damon, former Massachusetts Governor Mitt Romney, Tom Brokaw, and -- surprisingly -- Jerry Seinfeld. Landing Seinfeld was regarded as a particularly impressive coup, given the fact that the comedian was Leno's first guest on his primetime show last September and that he is currently plugging a show, The Marriage Ref, that is due to air on NBC beginning next week. In the meantime, Conan O'Brien surfaced on Twitter Wednesday, responding to the site's "What are you doing?" question by writing "Today I interviewed a squirrel in my backyard and then threw to commercial. Somebody help me." In his Twitter bio, O'Brien wrote "I had a show. Then I had a different show. Now I have a Twitter account."