Folie à Deux,” Lady Gaga will introduce audiences to Lee Quinzel, her version of the Joker’s love interest Harley Quinn from the DC comic books.

Joker: Folie à Deux pairs Joaquin Phoenix's Arthur Fleck with Lady Gaga's Harley Quinn, providing an intriguing backstory and questionable motives for the latter by the film's conclusion. Gaga is undoubtedly the biggest addition to Joker: Folie à Deux's cast,

Folie à Deux. Joker: Folie à Deux might be a courtroom drama, but it's also a surreal, dreamy, and twisted love story between Joaquin Phoenix's Arthur Fleck, AKA the Joker himself, and Lady Gaga's Harley "Lee" Quinn.