In this photo provided by CBS, David Letterman, host of the  Late Show with David Letterman,  is seated at his desk in New York on Thursday, April 3, 2014.
In this photo provided by CBS, David Letterman, host of the Late Show with David Letterman, is seated at his desk in New York on Thursday, April 3, 2014. During taping of the Thursday night telecast, Letterman announced that he will retire in 2015 when his contract expires. He announced no specific end date, telling his audience he expects his exit will be in "at least a year or so, but sometime in the not too distant future, 2015, for the love of God, (band leader) Paul (Shaffer) and I will be wrapping things up." (AP Photo/CBS, Jeffrey R. Staab) MANDATORY CREDIT, NO SALES, NO ARCHIVE, FOR NORTH AMERICAN USE ONLY ( Jeffrey R. Staab )