Lady Gaga, Robert De Niro, and a bunch of other weird celebrities popped by Jimmy Fallon's first Tonight Show

Though his debut didn’t draw quite as many viewers as Jay Leno’s farewell, Jimmy Fallon’s first Tonight Show did draw a boatload of weird celebrity guests. While Fallon’s scheduled guests included Will Smith, who joined him for an “Evolution of Hip-Hop Dancing” video, and U2, who played on the observation deck of the G.E. Building, other surprises included Stephen Colbert, Tina Fey, Lady Gaga, Seth Rogen, Joe Namath, Lindsay Lohan, Mike Tyson, Sarah Jessica Parker, Kim Kardashian, Rudy Giuliani, Robert De Niro, and Tracy Morgan—most of whom were there to supposedly settle a $100 bet they had with Fallon over whether he would ever host the program. Joan Rivers even dropped by to make her first Tonight Show appearance since she was ostensibly “banned” in 1987, after launching her own chat show on Fox. Other fun happenings worth noting: Spike Lee filmed the New York-centric opening, and The Roots have grown from an eight- to a 10-piece band with the move to 11:30.