David Michael Letterman is an American former television host, comedian, writer, producer, and actor. He hosted a late night television talk show for 33 years, beginning with the February 1, 1982, debut of Late Night with David Letterman on NBC, and ending with the May 20, 2015, broadcast of the Late Show with David Letterman on CBS. In total, Letterman hosted 6,028 episodes of Late Night and Late Show, surpassing friend and mentor Johnny Carson as the longest-serving late night talk show host in American television history.In 1996, David Letterman was ranked No. 45 on TV Guide‍ 's 50 Greatest TV Stars of All Time.详情