DAVID LETTERMAN'S last day on "The Late Show" will be Wednesday, May 20th, and a LOT of big name celebrities will be making appearances on the show over the next month to say goodbye.
They include: "Avengers" stars Robert Downey Jr. and Scarlett Johansson, "Ant-Man" star Paul Rudd, A-list celebrities likeOprah Winfrey, George Clooney, Julia Roberts, John Travolta, Tom Hanks, Bruce Willis, and Michael Keaton. . .
Comedy legends Tina Fey, Ray Romano, Will Ferrell, Billy Crystal, Jerry Seinfeld, Steve Martin, and Bill Murray . . .
And music guests Elvis Costello, Dave Matthews Band, and Mumford & Sons.
There's no word who will be on the FINAL episode yet. (For more, hit up Deadline.com.)
