Brendan Gleeson is joining Warner Bros. and DC Films’ Joker: Folie à Deux, the sequel to 2019’s Joker. Gleeson, who is known for the Harry Potter series and Mr. Mercedes, among other credits, has been cast in an unnamed role.

He joins returning stars Joaquin Phoenix as Arthur Fleck/Joker and Zazie Beetz as Sophie Dumond, as well as Lady Gaga who is reportedly playing Harley Quinn.

Todd Phillips, who helmed the first Joker, is back as director and co-writer, and Scott Silver, the writer behind the first movie is joining him to co-write the script. Little is known about the script other than rumors that it will have musical elements and take place in Arkham Asylum.

Unlike most comic character-based films, Joker relied heavily on drama rather than action by exploring untreated mental illness and the effects of exterior factors on someone in need. It became the highest grossing R-rated movie of all time with $1.07 billion at the global box office. Phoenix won an Academy Award for Best Actor for his performance. 

Joker: Folie à Deux is set for theatrical release on October 4, 2024 and production is expected to begin in December 2022.