Joker: Folie à Deux director Todd Phillips spoke to Variety about how Gaga's Harley is different than other takes on the character. "The high voice, that accent, the gum-chewing, and all that sort of sassy stuff that's in the comics, we stripped that away," he said. "We wanted her to fit into this world of Gotham that we created from the first movie."

The likelihood of hearing a "Mr. J" is low.

Gaga also discussed how she and co-star Joaquin Phoenix -- who proved with Walk the Line that he can carry a tune -- had to train themselves to sing worse. "We asked ourselves what would need to be true for two people to just break into song in the middle of a conversation?" she said. "Where does the music come from when no one can hear it but the characters? Neither Arthur nor Lee are professional singers, and they shouldn't sound like they are." They even both agreed to sing live on set, instead of using a pre-recorded track.