What is unexpected, however, is that this is going to be a standalone movie-and potentially a period piece-completely removed from WB's DC Extended Universe (or whatever it's called these days).
Variety reports that sources have confirmed "while studio negotiations are not yet underway, Phillips has made it clear that Phoenix is the top choice to star, ' and what's more, Joaquin has 'agreed" to the role.
He will reprise in the Suicide Squad sequel and the Harley Quinn spinoff.
Phillips' film, which he co-wrote with The Fighter and The Finest Hours scribe Scott Silver, is said to chronicle the Joker's early days as he rises to power as a criminal roaming and ruling the streets in the 1980s.
But this isn't the first time the "Her" actress has been considered for roles within the DC Comics family.
Phoenix has been considered for another villainous DC role in the past: Lex Luthor in "Batman v Superman: Dawn of Justice", but passed on that role, which ultimately went to Jesse Eisenberg.
These films are meant to "expand the canon of the iconic comic-book characters with unique story angles that aren't included in its current cinematic universe", said Variety. Phillips had allegedly met with Phoenix sometime in December to successfully convince the Inherent Vice actor to assume the role of The Joker.
Apparently, Wiseau believes that he is a worthy alternative if the deal with Phoenix falls through. He has most recently starred in Lynne Ramsay's You Were Never Really Here, Gus Van Sant's Don't Worry, He Won't Get Far On Foot and Garth Davis's Mary Magdalene.