LADY GAGA'S HARLEY QUINN BRINGS OUT THE BEST & WORST IN JOKER IN NEW ‘FOLIE à DEUX' TEASER: WATCH

In a brand new teaser for Joker: Folie à Deux, Lady Gaga‘s Harley Quinn tells Joaquin Phoenix's Arthur Fleck, "You can do anything you want" - which probably isn't the best thing to say to someone with an unpredictable neurological disorder who's currently institutionalized for committing several murders.

But alas, the pop superstar's character only wants the best - or worst - for the sequel's titular character, who meets Quinn while awaiting trial for his crimes as Joker and embarks on a fever-dreamlike musical romance with the "Born This Way" singer in the Todd Phillips-directed project. "Well I'll tell you what's changed," Phoenix says in the new teaser posted Monday (Sept. 9). "I'm not alone anymore."

The one-minute preview also features new clips of Gaga and the Napoleon actor kissing in a burning room, sharing cigarette smoke through jail cell bars and waltzing under streetlights. At one point, Quinn reminds her beau who he is over a clip of her riding an elevator with her signature smudged clown makeup: "You're Joker," she says, while the video cuts to a scene of Phoenix winding up to bash in the head of a judge presiding over a courtroom.

The new trailer comes less than a month ahead of Folie à Deux hitting theaters Oct. 4. Ahead of its release, the 13-time Grammy winner and Phoenix promoted the movie at the Venice International Film Festival in the first week of September, where Gaga opened up about the "special and extremely nuanced" way they approached music while shooting.

"I wouldn't necessarily say that this is actually a musical," she said during a panel at the festival. "The way that music is used is to give the characters a way to express what they need to say, because the scene and dialogue wasn't enough. The pianist that was on set with us was sort of like an actor off camera in the scene with us. For me it was a lot about unlearning technique and forgetting how to breathe, and allowing the song to completely come out of the character."

Watch the new teaser for Joker: Folie à Deux above.