People were still scratching their heads over the appearance of Jay Leno with Oprah Winfrey in a promotional ad for David Letterman's show during Sunday's Super Bowl telecast. On his Jay Leno Show , which airs for the last time tonight (Tuesday), before Leno resumes his rivalry with Letterman when he returns to the Tonight show next month, Leno gave his tongue-in-cheek version of how the promo came about. "Letterman and I hadn't seen each other in over 18 years. We lost touch. He found me on Facebook. He made a friend request, I accepted, and we hooked up and watched the game." As for the day of the actual shoot, Leno said, "I walk in and I see Dave, and he puts out his hand and we shake hands. And you know, whatever happened for the last 18 years disappeared. It was great to see my old friend again." On his show, Letterman sounded less sentimental, saying that he wanted to thank "the actors who played Oprah and Jay Leno."