According to Variety, Phoenix is Phillips choice to play The Joker.
Legendary filmmaker Martin Scorsese is said to be attached as producer to the movie, which will lend inspiration from his films "Taxi Driver" and "Raging Bull", both of which are dark masterpieces, Comicbook.com reported. WB had no comment.
To recall, it was previous year when Warner Bros announced that it would be producing a solo "Joker" movie that will be separate from the studio's current brand of DC movies, the DCEU, which interconnects the story of other DC movies.
"You Were Never Really Here" actor Joaquin Phoenix may star as the Joker in the already announced solo non-DCEU (DC Extended Universe) movie about Batman's most famous nemesis.
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Insiders stress that Jared Leto, who starred in "Suicide Squad" as the Joker is still on board as the character in the DC universe and that this Phoenix has no effect on what happens with Leto's character in future DC films.
Phillips, who has also worked on Road Trip and War Dogs, will direct the movie and co-write it with Scott Silver.
Confusingly, it has been reported that he will likely reprise the role in Suicide Squad 2 and the Joker-Harley Quinn movie that is now in development. He was asked by Marvel to play the Hulk in The Avengers and was approached again for the titular role of Doctor Strange.
And while Phoenix has turned down several other comic book cinematic roles including Lex Luthor in "Batman v Superman: Dawn of Justice", according to Variety, it would seem that he is keen to experiment with the Joker's character.
The film would possibly be able to expand and explore more opportunities within the DC Comics world, with more details to further the iconic comic-book characters.