David Letterman will tape a guest appearance for The Oprah Winfrey Show on Sept. 10 at no less than Madison Square Garden - a sit-down that essentially represents Part 3 of the pair's "All Is Forgiven Tour," which began in 2005 when O dropped by Late Show and then continued when they popped up together in a surprise Super Bowl commercial. Prior to all that, the two were engaged in a decade-long, post-Uma/Oprah "rift" of sorts, as Winfrey turned down repeat invites to do Dave's talker.