Lady GaGa is in early talks to star in the 'Joker' sequel, which is set to be a musical.

The 'House of Gucci' actress is said to be in discussions about taking on the role of Harley Quinn - who was played by Margot Robbie in 2016 and 2021 movies 'Suicide Squad' and 'The Suicide Squad' - in Todd Phillips' follow-up film.

Joaquin Phoenix played the titular character in 2019's 'Joker', but sources have told The Hollywood Reporter that Warner Bros. are yet to close a deal for him to star in the sequel.

If Gaga signs up for the movie then she is expected to play Quinn, who has an on/off abusive relationship with Joker.

Sources have also told the publication that the motion picture will be a musical movie.

Phillips - who directed the original psychological thriller - has been working on the script for the sequel with Scott Silver, who he co-wrote the first movie alongside.

Last week, he appeared to confirm the sequel will be titled 'Joker: Folie a Deux'.

The French phrase translates as "shared madness" and is used to describe a delusion shared by two people in close proximity.

It wouldn't be the first time Gaga and Phillips have worked together after he produced 2018 musical movie 'A Star is Born', which featured Gaga and Bradley Cooper - who co-produced 'Joker' alongside Phillips and Emma Tillinger Koskoff - in the lead roles.

The first 'Joker' movie was a huge box office success, grossing more than $1 billion on a budget of $55 million.

The film was nominated for 11 Academy Awards and Phoenix won Best Actor for his portrayal of mentally disturbed Arthur Fleck, who evolves into the iconic Batman villain by the end of the story, and composer Hildur Guðnadóttir won the Best Original Score gong.

Phillips received huge acclaim for the movie, but the director previously claimed audiences overlooked one of the film's central themes.

He explained: "If I had to drill down on one overarching theme for me, it’s about the power of kindness and a lot of people miss that.

"I think if you don’t see that you either don’t have a soul or you’re being reductive to make up for your own struggles in that area.

"But, really, to me, that’s where it started from and there are other things in the movie like lack of love, the lack of empathy in society, and childhood trauma, but the power of kindness really runs through this film."