After Joan Rivers walked out on her CNN interview with host Fredricka Whitfield, viewers accused the iconic comedian of pulling a PR stunt to further promote her new book Diary of a Mad Diva. Rivers, of course, denied those allegations, saying, “I do not do, and never have done, PR ‘stunts.’ The CNN interviewer was a news reporter and not an entertainment reporter. She did not seem to understand we were talking about a comedy book and not the transcripts from the Nuremberg Trial.” But when Rivers visited Late Show with David Letterman last night, Letterman was all too happy to bring it up in his own special way— by walking out on Rivers. Check out the video below. You can also watch the Rivers interview with Whitfield so you can properly put the Letterman appearance in proper context.