According to Flickering Myth on Saturday, a couple of weeks prior "Batman vs. Superman's" director of photography Larry Fong tweeted an image of a single card embedded in what appeared to be a concrete wall. This gave rise to a lot of buzz and speculation on the appearance of the Joker in the "Man of Steel" sequel. TMZ caught up with "300: Rise of an Empire's" Callan Mulvany who has been cast in the film, but as character not yet known. Even the Internet Movie Database has him listed, but with no character name in the credits.
The role was considered by Warner Brothers as "newly made" and the reporter who met up with Mulvany figured that since he's Australian as well, this could be some kind of homage paid to fellow "Aussie" Heath Ledger. This could be going out in a limb in thinking as such, but Mulvany said he couldn't even talk about what's going on with the film. He was also "tipped" to play a big-time villain character prior to the announcement of the celebrity's casting.
There are also things to consider with the current known roles. For one, there is already a superhero rich film. Batman, Superman, Wonder Woman, and Cyborg were already revealed, but Jesse Eisenberg was announced so far as the only villain they'd be going up against. So logic would dictate one would have to balance the scales of good vs. evil.
The film had officially started shooting in Birmingham, Mich. and recently pictures of Henry Cavill had been popping up online in fans' twitter feeds and other social media locations. It seems the "Man of Steel" actor had been showing up at local watering holes during his downtime and enjoying the company fans in comedic poses.