After “Joker” became a $1 billion hit for Warner Bros. Pictures in 2019, a sequel seemed inevitable.

Cut to five years later and the follow-up, “Joker: Folie à Deux,” is set to hit cinemas this Fall and is expected to be one of the biggest films of the year.

This time Joaquin Phoenix will share the spotlight with Lady Gaga who takes on the role of Harley Quinn. Gaga has already scored plenty of acclaim for her work in films like “A Star is Born” and TV like “American Horror Story”.

However casting director Francine Maisler (“Dune,” “Challengers”) revealed at a Karlovy Vary Talk (via Deadline) that everyone will be surprised by Gaga’s work on the film and that she exceeded any expectations people might have placed on her:

“She’s so good in it, you guys. She’s going to blow your mind. I didn’t suggest Lady Gaga. It wasn’t my idea. That was Todd Phillips, before me. But I will tell you, she’s really surprising – and really good. I saw it and I was really surprised.

I mean, we all knew what she could do in A Star is Born, but I thought, ‘Oh, well, that’s kind of in her wheelhouse.’ Something she could do and just be real. But this…Man, she’s good. Joaquin blows your mind, but that she could keep up with him, and be real – and not just wiped off the screen by what that role is and what the performance is – shows she’s good.”

Gaga has previously said she’s doing her own version of the character, one very authentic to the new movie which has been dubbed a musical of sorts albeit not clear how that element fits in.

“Joker: Folie A Deux” opens in cinemas on October 4th.