Lady Gaga and Joaquin Phoenix in Joker: Folie A Deux. LOS ANGELES – Joker (2019) was an unusual entry in the superhero movie genre. The deeply psychological origin story of the eponymous villain – a key character in the Batman universe – cared more about the mental collapse of its protagonist than big action scenes.

But the creative gamble paid off: The film grossed more than US$1 billion (S$1.29 billion) globally and picked up Best Picture, Best Director and Best Adapted Screenplay Oscar nominations, eventually winning Best Actor for its star Joaquin Phoenix, as well as Best Original Score. Departing from convention yet again is the follow-up Joker: Folie A Deux, which opens in Singapore cinemas on Oct 3.

And at its recent Los Angeles premiere, American writer-director Todd Phillips says it may not be the sequel fans expect. For one thing, it incorporates musical elements, a move that has sparked curiosity and debate among fans. And this time, the story dives into the psychosis of not one but two characters, with the French phrase in the title – which means “madness of two” – referring to a psychiatric condition where delusions spread from one person to another.

American actor Phoenix, 49, reprises his role as Arthur Fleck, a failed comedian and party clown who becomes the murderous villain known as Joker. While awaiting trial for his headline-grabbing crimes, he is put in a mental asylum, where he forms a romantic connection with fellow inmate Harleen Quinzel,.