Joker: Folie À Deux Trailer Unites Joaquin Phoenix’s Joker With Lady Gaga’s Harley Quinn

Is it a musical? Is it not? That's been the big question on everyone's lips about Todd Phillips' Joker sequel, known as Joker: Folie À Deux. And the first teaser trailer doesn't exactly clear it up (Phillips on stage at Tuesday's CinemaCon event said he doesn't consider a musical but that music is a key element), but it's certainly full of tune-age.

More as predicted, the new film finds Joaquin Phoenix's Arthur Fleck in Arkham Asylum, and it's there he meets Lady Gaga's Harley Quinn – here not the traditional psychologist he ends up corrupting, but a fellow inmate (and something of a fan), who forms a love connection with our hero.

Expect twisted romance, songs, performances, violence and — yes! Steve Coogan too.

Joker: Folie À Deux will be in cinemas on 4 October.