“I identify as a clown,” he says, understating his range as a performer, having portrayed George on Broadway in Who’s Afraid of Virginia Wolf and Mr. Noodle on Sesame Street in Elmo’s World. And yet even a career as luminous as his has its disappointments: “I once asked John Cleese to play Pozzo in Waiting for Godot. Wouldn’t it have been great? But we just never made it work.”