After months of speculation, we can finally confirm that John Mayer will be joining Bob Weir, Billy Kreutzmann and Mickey Hart this Fall on the latest and greatest Grateful Dead side project. Coming off of the massive Fare Thee Well shows, they’ll be joined by Jeff Chimenti on keys and bassist Oteil Burbridge at Madison Square Garden for a special Halloween affair. The announcement did not mention any additional shows with this lineup beyond the confirmed Halloween date at MSG; but if the rumors stand up, we can expect a full tour announcement from Dead & Company sometime in the coming weeks. In the meantime, enjoy this video of Bobby & Johnny ripping through a killer version of Truckin’ on The Late Late Show from earlier this year…