The new film stars Joaquin Phoenix once again in his Oscar-winning dual role as Arthur Fleck/Joker, opposite Oscar winner Lady Gaga ("A Star Is Born").

"Joker: Folie À Deux" finds Arthur Fleck institutionalized at Arkham awaiting trial for his crimes as Joker. While struggling with his dual identity, Arthur not only stumbles upon true love, but also finds the music that's always been inside him.

The film also stars Oscar nominees Brendan Gleeson ("The Banshees of Inisherin") and Catherine Keener ("Get Out," "Capote"), alongside Zazie Beetz, reprising her role from "Joker."

Phillips, who was nominated for Oscars for directing, writing and producing "Joker," directed "Joker: Folie À Deux" from a screenplay by fellow Oscar nominee Scott Silver & Phillips, based on characters from DC.  The film was produced by Phillips, Oscar nominee Emma Tillinger Koskoff and Joseph Garner.  Lady Gaga served as music consultant.  The film's executive producers are Michael E. Uslan, Georgia Kacandes, Silver, Mark Friedberg and Jason Ruder.