Leave it up to the Joker to laugh at himself.

Joaquin Phoenix recently told Empire what it was like singing with Grammy winner Lady Gaga for their upcoming film, “Joker: Folie à Deux.”

And it sounds like things got off to a rocky start.

“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,” Phoenix said jokingly.

But he admitted that, despite her knee-jerk reaction, the “Born This Way” singer was ultimately pretty supportive of his amateur crooning.

“Gaga was always very encouraging of just, ‘go with what you feel, it’s fine,’” Phoenix added. “For somebody who’s not a performer in that way, it can be ... uncomfortable to do that, but also very exciting.”

He’s showcased his musical chops before, though. In the 2005 Johnny Cash biopic “Walk the Line,” he did all his own singing.

“Joker: Folie à Deux” is a musical sequel to Todd Phillips’ 2019 movie, “Joker.” Phoenix will reprise his Oscar-winning role as Arthur Fleck/Joker in the film, while Gaga will be introduced as his love interest, Lee/Harley Quinn.

Music and singing will play a pivotal role in the film, and although Gaga has plenty of experience belting out hits, she previously admitted to Empire in a separate piece that she struggled a bit with her vocals as well.

“People know me by my stage name, Lady Gaga, right? That’s me as that performer, but that is not what this movie is,” Gaga explained. “I’m playing a character, so I worked a lot on the way that I sang to come from Lee, and to not come from me as a performer.”

“It was unlike anything I’ve ever done before,” she said. “I’m a trained singer, right? So even my breathing was different when I sang as Lee.”