Joaquin Phoenix as Arthur Fleck in "Joker: Folie à Deux."
Warner Bros.
- A "Joker" sequel titled "Joker: Folie à Deux" is set for release on October 4.
- The movie stars Joaquin Phoenix as Arthur Fleck and Lady Gaga as Harley Quinn.
- The film is a musical and will reportedly include at least 15 new versions of well-known songs.
Joaquin Phoenix is brushing off his dancing shoes and reapplying clown makeup to reprise his role as Arthur Fleck in Todd Phillips' upcoming "Joker" sequel.