David Michael Letterman (born April 12, 1947) is an American television host, comedian, writer and producer. He hosted late night television talk shows 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 Late Show with David Letterman on CBS. In total, Letterman hosted 6,080 episodes of Late Night and Late Show, surpassing his friend and mentor Johnny Carson as the longest-serving late night talk show host in American television history. In 1996, Letterman was ranked 45th on TV Guide's 50 Greatest TV Stars of All Time. In 2002, The Late Show with David Letterman was ranked seventh on TV Guide's 50 Greatest TV Shows of All Time.