David Michael Letterman (born April 12, 1947) is an American television host and comedian. He hosts the late night television talk show Late Show with David Letterman, broadcast on CBS. Letterman has been a fixture on late night television since the 1982 debut of Late Night with David Letterman on NBC. In 1996, David Letterman was ranked #45 on TV Guide's 50 Greatest TV Stars of All Time. In 2013, Letterman surpassed friend and mentor Johnny Carson as the longest-serving late-night talk show host in TV history, at 31 years. On April 3, 2014, Letterman announced he will retire sometime in 2015 around the conclusion of his current contract which ends in August 2015. CBS announced that Stephen Colbert, comedian, writer and host of Comedy Central's The Colbert Report since 2005, will take his place.