The Wrap has “an insider exclusive” that the upcoming Joker standalone film will feature the villain as a failed comic from the 1980s who becomes demented and evil. The website goes on to suspect that, given Martin Scorsese’s involvement as producer in the film, it would be something along the lines of the acclaimed director’s 1982 movie The King Of Comedy.
And since The Hangover’s Todd Phillips is directing, it would make sense that the movie would go in a more dark comedic direction.
The idea of the Joker as a struggling funnyman was also featured in the 1988 graphic novel The Killing Joke:
Certainly, this takes the Joker in a quite different direction than his last three cinematic incarnations: the “classic” gangster of 1989’s Batman, the anarchic possible ex-military vet of 2008’s The Dark Knight, and the…well, Jared Leto from 2016’s Suicide Squad.
The article also says that Joaquin Phoenix “is close to a deal” to star in the film, with production to possibly start mid-to-late 2018.