Lady GaGa says she and Joaquin Phoenix "laughed a lot" making "dark" movie 'Joker: Folie a Deux'.

The 38-year-old pop star is the Harley Quinn to Joaquin's Joker in the upcoming psychological thriller film, and she has revealed there was "never a dull" moment working with her hilarious co-star on the sequel to 2019's 'Joker'.

Speaking on the red carpet at the flick's premiere in London on Wednesday (25.09.24), she said: "I loved working with Joaquin, it was never a dull day at the office.

"It was always super interesting.

“He’s very funny all the time, as dark as the world of 'Joker' is, we laughed a lot on set, and we were always just being as organic as possible."

As well as her starring role, the 'House of Gucci' star has recorded the 13-song album 'Harlequin' to accompany the film.

Joaquin recently recalled Gaga "spitting up coffee" when she first heard his singing voice on set.

He told Empire magazine: "I do seem to remember her spitting up coffee the first time I sang, so that felt good, that was exciting, and made me feel confident.

"Gaga was always very encouraging of just, 'Go with what you feel, it's fine.'"

He added: "For somebody who's not a performer in that way, it can be... uncomfortable to do that, but also very exciting."

Joaquin explained that his mentally ill character's singing voice is intentionally imperfect.

The Oscar-winning star said: "It was important to protect that with poor phrasing and occasional bum notes.

"Arthur grew up hearing his mother play these songs on the radio. He's not a singer, and he shouldn't sound like a professional singer. He should sound like somebody that's taking a shower and just bursts out into song."