Longtime friend Billy Crystal was Jay Leno’s first guest on The Tonight Show back on March 25, 1992 when Leno took over the late night chair from the legendary Johnny Carson. He promised his old buddy to be his final guest, too. “A promise made. A promise kept,” Crystal said last night. His appearance on the show was not limited to remincising about their old stand-up days. The multi-talented actor then conducted a musical send-off for the 63-year old late night host, bringing out back-up singers for a special rendition of The Sound of Music‘s hit song, “So Long, Farewell.” This version featured some amazing cameos from Jack Black, Oprah Winfrey, and more! Check it out!