Rare is the musical that can waste a pop megastar of Gaga’s caliber. Rarer still is the one that will send you away humming no tune, tapping no toes. If you bought a ticket to “Joker: Folie à Deux,” then the joke — yet again — is on you.

"Well, I know what I'm going to be showing him later. That's so cool, thanks for showing me that," the singer said.