There’s a very specific formula to talk shows: ask a few questions, sets up a pre-arranged anecdote, roll a promotional clip. There are, of course, a few twists that have been introduced in recent years to add some excitement—and encourage a viral video. If you’re sitting down with Ellen, there’s a chance a clown will pop out to scare you; if you’re making an appearance on Jimmy Fallon, you may be asked to participate in a lip sync battle; if you’re dropping by James Corden, you could end up eating a calf’s brain. The onus to create an amusing talk show bit falls heavily on the celebrity guest, and every once in a while, an unexpected A-lister gifts the world a moment of spontaneous, hilarious and endearing entertainment. With the Talk Show Guest Hall of Fame, we commemorate these celebs. Since the day Bradley Cooper and Lady Gaga stepped out together at the Venice Film Festival , holding hands down the red carpet into the premiere of A Star is Born , their off-screen relat...