At a Late Show taping on Thursday David Letterman announced his retirement for 2015.
The news was first indicated in tweet from former R.E.M. bassist Mike Mills, and later seconded by CBS Evening News anchor Jeff Glor.

Rolling Stone notes that Letterman signed a two year contract a year ago and by the time it is over he will have spent 22 years on CBS's The Late Show, making 33 years in late night with the addition of his time on NBC's Late Night.
According to Daily News Letterman told his audience that his first call was to CBC CEO Les Moonves and he made it just before the taping. He said "He and I have had a relationship for years and years and years, and we have had this conversation in the past, and we agreed that we would work together on this circumstance and the timing of this circumstance. And I phoned him just before the program, and I said 'Leslie, it's been great, you've been great, and the network has been great, but I'm retiring."