Watch: First 'Joker: Folie à Deux' Trailer Drops, and Fans are Already Going Wild

The first trailer for Todd Phillips' "Joker" followup has arrived. Fans can't wait for the Oct. 4 release date of the film, which pairs Joaquin Phoenix and Lady Gaga as a couple who are, shall we say, madly in love. "Folie à Deux," indeed!

The upcoming film carries a hefty $200 million price tag and sees Phoenix "reprise his Oscar-winning role as Arthur Fleck (who later becomes Batman's notorious foe) and conspire with Lady Gaga as the equally twisted Harley Quinn," Variety notes.

As the trailer commences, failed standup comedian Arthur Fleck (Phoenix) is alone in his cell at Arkham Asylum, an institution for the criminally insane. Guards escort him through the asylum's corridors, where he exchanges glances with Harley Quinn (Lady Gaga), and love takes hold.

Later, as they sit side by side in an audience, Harley Quinn takes Arthur's hand: "Let's get out of here," she suggests.

The trailer is packed with movie musical moments (a spotlight shining down, Fleck walking in the rain as the black umbrellas of his minders suddenly become vibrant with color, the lovers doing dance numbers that include a set piece in a romantic rooftop setting), all to the strains of a lushly orchestra rendition of "What the World Needs Now."

"We use music to make us whole," a voiceover says, "to balance the fractures within ourselves." Quinn is seen in a room rehearsing with others, a score in her hand. The implication is that the inmates of Arkham are receiving some sort of music therapy.

But those images are interspersed with glimpses of violence and mayhem: An explosion rips through a crowded room, the lovers run up a long hallway as flames roar behind them, a rioter hurls a trash can through a storefront window, and Quinn pulls a gun on Fleck before, in the very next cut, she is seen painting her lips with a smear of blood in imitation of the Joker's infamous smile.

"So," Steve Coogan, in an unspecified role, asks Phoenix's Fleck, "what changed, Arthur?"

"well, I'll tell you what changed," Fleck replies, as the montage of intriguing images continues. "I'm not alone any more. That's that we should be talking about!"

Fans on social media responded with enthusiasm:

"Little is known about the actual plot of the sequel, which is reportedly a jukebox musical," Variety noted, adding that according to Phillips, "that categorization isn't entirely accurate, though it will feature plenty of song and dance numbers."

"I like to say it's a movie where music is an essential element," Variety quoted the director as saying evasively. "It doesn't veer too far from the first film."

Watch the trailer below.