Brendan Gleeson joined the 'Joker' sequel to work with Joaquin Phoenix.

The 67-year-old actor has been cast in 'Joker: Folie a Deux' and revealed that he joined the Todd Phillips film to collaborate with Phoenix after the pair starred in the 2004 film 'The Village' together.

Brendan confirmed that the success of the original movie – with Joaquin claiming the Best Actor Oscar for his portrayal of Arthur Fleck/Joker – also played a part in persuading him to take the role.

Asked how the 'Joker' sequel appealed to him, he told Collider: "It wasn't the material, which is a great way to get me out of having to answer any questions about the criteria.

"It was the achievement of the first film. I worked with Joaquin before on 'The Village'... And so I knew him from then."

Brendan continued: "And that performance, I'm still in awe of it. That performance as Joker, in that first movie. It was one of the most extraordinary achievements I've ever had.

"And for Todd to have – Worked the movie around to allow for that, I didn't have to be asked twice. I really didn't."

Lady GaGa has been cast in the sequel as Harley Quinn and Margot Robbie – who played the Joker's love interest in three movies – loves the idea of the character being passed around by "great actors".

The 32-year-old actress said: "It makes me so happy because I said from the very beginning, all I want is for Harley Quinn to be one of those characters, the way Macbeth or Batman always gets passed from great actor to great actor.

"And I feel like in not so many cases are they female characters.

"Queen Elizabeth I, but like beyond that — which I got to have a crack at as well, which I was honoured to do. I was like, 'Wow, Cate Blanchett did Queen Elizabeth I. Now I get to.' "