Steve Coogan makes surprise cameo in Joker: Folie à Deux trailer

Steve Coogan's fans were shocked to discover his cameo appearance in the new trailer for Joker: Folie à Deux.

The British comedian and actor popped up in the latest trailer, which was unveiled at CinemaCon in Las Vegas on Tuesday.

Details about his character remain under wraps, however, Coogan appears to play an authority figure with an American accent.

In the clip, he asks Joaquin Phoenix's character Arthur Fleck/Joker, "Tell us, what's changed, Arthur?"

Arthur replies, "I'll tell you what's changed - I'm not alone anymore."

Joker: Folie à Deux, the sequel to 2019's Joker, follows Phoenix's Arthur as he meets his love interest Harley Quinn, played by Lady Gaga, in Arkham Asylum. In the comics, the famed characters meet when she becomes his psychiatrist in the prison, however, in Todd Phillip's film, she appears to be a fellow inmate.

During the trailer's presentation, Phillips addressed the sequel being described as a musical.

"We never talked about it like that," he said, according to The Hollywood Reporter. "I like to say it's a movie where music is an essential element. To me that doesn't veer too far from the first film... Arthur has music in him (in the first film). He has a grace to him."

Joker: Folie à Deux also stars Zazie Beetz, Catherine Keener and Brendan Gleeson. It will be released in cinemas in October.