Due to the fact that Henry Cavill was shooting Mission: Impossible - Fallout when he was required to return for Justice League's reshoots, he was still sporting the moustache he'd grown to play August Walker. Joss Whedon and Warner Bros. attempted to remove his facial hair with VFX, but the result was comical, and his creepy CGI jawline has become a point of ridicule since the superhero ensemble's release in 2017.
While Zack Snyder obviously shot Superman's original scenes in the movie (which were largely replaced with Whedon's reshoots), a new report from Heroic Hollywood claims that, "there is a rumor that Zack Snyder will have to shoot Henry Cavill’s face against a green screen at the very least for special effects purposes, because the current reference material of Cavill from the theatrical cut of Justice League is of him with the mustache."
"A special effects insider tells Heroic Hollywood, how that would work is that the visual effects house hired for the Snyder Cut will reshoot Cavill’s face and map that onto the existing footage."
"If Cavill were to go into the studio, and assuming that he’s in the relative same shape, it might be easier to reshoot his whole body and performance, paint out the old footage and replace it with the new and current special-effects footage," the site explains. "A lot also depends on the complexity of the shots Snyder wants to use and how many they have to do."
So, these won't be traditional "reshoots" featuring Cavill, but this could explain why it was recently revealed that the budget for Zack Snyder's Justice League will be well beyond the originally reported $30 million. Whether this will lead to additional scenes that weren't going to be in Snyder's theatrical cut is hard to say, but it's certainly intriguing to think about.
We don't know when this FX work will take place, but the movie/TV series is set for a 2021 debut.