The post shows a black-and-red video of Phoenix and Gaga's shadows joining together, along with the caption announcing the sequel's release date, Oct. 4, 2024.
ET has reached out to Warner Brothers for comment.
Details about Gaga’s role in the film have not been released, but it’s speculated that she will star as the Joker’s co-conspirator, Harley Quinn -- his psychiatrist at the asylum who becomes his partner in crime.
Gaga's portrayal of the Clown Prince of Crime's notorious first lady would be the third current imagining of the role. Margot Robbie plays Harley on the Suicide Squad and Birds of Prey side of the DC Comics Extended Universe, while Kaley Cuoco voices the legendary baddie in HBO Max's animated series, Harley Quinn.
The Joker sequel would follow Gaga's buzzworthy performance in 2021’s House of Gucci and her Oscar-nominated role in 2018’s remake of A Star Is Born.
Joker is the origin story of was Batman’s arch nemesis, Arthur Fleck, and follows as he goes from comedian to villain. The film grossed an estimated $1 billion at the box office and earned Phoenix an Academy Award for Best Actor.
The script for Folie à deux was written by Todd Phillips, who is also set to direct the film and headed up the 2019 movie.