According to Variety, $25M worth of reshoots are underway for Zack Snyder and Joss Whedon's Justice League, and amidst their story on the matter - which details the various scheduling conflicts (or lack thereof) for the bulk of the Justice League cast - is this interesting tidbit:
“Justice League’s Man of Steel had expected to be able to finish shooting the sixth Mission: Impossible film before needing to don Superman’s spandex again. That has not been the case, however, as the new scenes that are being shot have required him to jump back and forth from each production. Because of this, a mustache he grew for his character in the Mission: Impossible sequel will have to be digitally removed in post-production. Paramount, which is distributing the Mission: Impossible sequel, would not allow Cavill to shave the facial hair while production was taking place."
Yes, Henry Cavill will undergo his Justice League reshoots while rocking a full-blown Tom Selleck mustache, and Warner Bros. is gonna have to pay to have it digitally removed from the film. I suppose the bigger news here might be that Superman's appearing in Justice League, but come on: none of you really believed he wouldn't make an appearance, did you?
Here's an Instagram post showing Cavill in Mission: Impossible 6 mode, just for the record.
(Note: Header Photoshop via the great Cameron Stewart)