Robert De Niro is reportedly in talks to join Phoenix in the comic book movie, playing the character of a talk-show host who is partly responsible for the Joker's descent into madness. Insiders say that the script is linked to 'King of Comedy', so it would make sense for De Niro to come on board.
De Niro hasn't yet starred in any comic book adaptations or superhero movies, but insiders say that director Todd Phillips's pitch that the Joker movie is more in line with the '80s crime-noir genre appealed to him. The film is rumoured to be set in early 1980s Gotham.
With shooting set to begin in New York this September, this deal could be wrapped up very quickly.