Since the box office flop that was Justice League, Warner Bros have been taking a different approach to their DC Comics property.
Currently shooting is a Joker solo movie starring Phoenix, despite Jared Leto having played the character in Suicide Squad just two years ago.
This take on the Clown Prince of Crime is an origin story set in 1980s Gotham City.
Phoenix plays Arthur Fleck, a struggling comedian in a Batman spin-off prequel that also includes Thomas Wayne, Alfred the Butler and even a young Bruce Wayne.
While much of the plot is kept under-wraps, what could be a major spoiler has been posted on Instagram.
One user, who has put up a number of set photos and videos, has shared a piece of information of what they claim is a source on Joker.
The following isn’t confirmed officially so should be taken with a grain of salt, even though it’s claimed this is not a rumour.
WARNING POTENTIALLY MAJOR SPOILERS FOR JOKER MOVIE AHEAD
In a post ragealghul_creations writes: “From set: Arthur is Thomas Wayne’s son. Thomas had an affair with Arthur’s mother, so yes he’s Bruce’s half-brother.”
The leaker added: “First off, Thomas is in his mid 60’s, Arthur is in his late 30’s early 40’s, more than possible for him to be the bastard son.
“Am I excited about this? Ehhh I don’t know, if done right it could be cool and a driving force for Arthur to hate Bruce in the future but we’ll see, and stop asking me about the source, I can’t get him in trouble so I obviously won’t put his name out there but he had several scenes back in Brooklyn and Newark among other locations so he’s seen a lot, and showed me proof of what he was saying and went into great detail.
“I don’t give a damn if you believe it or not but I don’t post things on here and say fact unless 100% proven. So idiotic comments like fake, bulls*** and saying I’m making stuff up will get you blocked in a heartbeat. PS. NOT A RUMOR, THIS IS CONFIRMED 100%.”