David Letterman returned to the Ed Sullivan Theater on Monday night for the first time since his retirement in 2015, appearing as a guest on "The Late Show with Stephen Colbert." He was welcomed with a warm reception and was grateful to be back, joking that he was there because his son didn't believe he had a show. He and Colbert recreated a selfie they took in 2014 and Letterman thanked Colbert for having him, showing that he still has a place in the hearts of late night fans.