Joker: Folie à Deux first clip sees Lady Gaga's Harley Quinn and Arthur Fleck break out into song

The first clip from Joker: Folie à Deux is here, and it sees Lady Gaga's Harley Quinn (named Lee in the movie) bonding with Joaquin Phoenix's Arthur Fleck in a fittingly unusual way. 

In the footage, which you can see below, both characters appear to be in Arkham. Lee comments that she watched Arthur's appearance on Murray Franklin's talkshow, which ended with Joker fatally shooting the host. Lee, though, was hoping for exactly that outcome – and then the duo break into a quiet rendition of 'Get Happy.' 

As you can tell from the fact that both Lee and Joker appear to be patients in Arkham – a twist on their comic book origin, which sees Harley as a therapist and Joker her patient – the movie will be a departure from the source material. 

"The high voice, that accent, the gum-chewing and all that sort of sassy stuff that's in the comics, we stripped that away," director Todd Phillips has previously revealed of Gaga's take on Harley. "We wanted her to fit into this world of Gotham that we created from the first movie."

Gaga herself has also shared that Lee will be an all-new creation. "You know my version of Harley is mine, and it's very authentic to this movie and these characters," she said. "I've never done anything like I've done in this movie before, so it's all going to be completely brand new and really fun."

Joker 2 hits theaters this October 4. In the meantime, check out our guide to all the upcoming DC movies and TV shows for everything else that's in store.