Gaga’s Harley Quinn joins the Clown Prince of Crime in Joker: Folie à Deux trailer

This weekend will be all about San Diego Comic-Con and the hotly anticipated theatrical release of the summer blockbuster Deadpool and Wolverine, but Warner Bros. is already looking ahead to the fall. The studio dropped the official trailer for Joker: Folie à Deux, the sequel to 2019's smash hit Joker, starring Joaquin Phoenix. This time, he's joined by fellow asylum inmate Harley Quinn (Lady Gaga) to bring a comic book criminal partnership for the ages to gritty life.

(Spoilers for 2019's Joker below.)

Joker was intended to be a standalone film—part of DC Films' decision to move away from the shared-universe approach of its prior franchise DCEU films. (DC Studios CEO James Gunn is now calling it the "DC Elseworld" project.) It had no relation to the Justice League films that came before, so that freed Phillips to create his own darker, grittier version of this iconic character. He cited Martin Scorsese films like Taxi Driver, Raging Bull, and The King of Comedy among his influences. There's no real origin story for the Joker in the comics—not a definitive one, anyway—so Phillips and screenwriter Scott Silver were able to cherry-pick the canonical elements they needed and make up the rest. (In Batman: The Killing Joke, for instance, the Joker is a failed comedian.)