Henry Cavill has already filmed a Superman cameo for The Flash, but an internal shakeup of the DCU might mean the scene won't be included in the film.
Henry Cavill has already shot a Superman cameo for the upcoming DC film The Flash. Cavill first appeared as Superman in the DC Universe in 2013's Man of Steel, and would go on to reprise the role in Batman v Superman: Dawn of Justice in 2016 and Justice League in 2017. Cavill's continued role as Superman was unclear for several years before he made a cameo appearance in the post-credits scene of Black Adam this year. However, newly-appointed co-CEOs of DC Studios James Gunn and Peter Safran have recently announced plans to make some major changes to the DC Universe, which may include some serious re-tooling of the DC heroes cast in the early days of the DCEU. The next Justice League character to star in their own film will be Ezra Miller fronting The Flash, which is set to premiere on June 16.
In a report by The Hollywood Reporter, Cavill has already filmed a cameo as Superman in The Flash. Cavill shot his part back in September, and Jason Momoa's Aquaman is also expected to make a cameo appearance. However, with Gunn and Safran intending to make big changes to DC in the coming weeks, there is reportedly debate inside the studio as to whether Cavill's cameo should stay in the film. If Gunn and Safran nix Cavill's Superman from the DCU entirely, they might not keep the Superman cameo so that DC isn't making future promises it can't deliver on.
As of yet, no plans have been finalized as to whether Cavill's cameo will make it into the final cut of The Flash. Though the Justice League's future is uncertain at the moment, DC still fully intends to release The Flash, a film which has been on DC's mind since 2014. Though Miller's legal troubles have led to some speculation over the fate of the film and of the character himself, and the film's release date has been moved several times, the June 16 premiere is still currently fixed. Cavill and Momoa's cameos, as well as the appearance of Ben Affleck's Batman, firmly affix the film to the current iteration of the DCU and its Justice League characters.
Cavill's cameo appearance at the end of Black Adam was met with great excitement by DC fans, who were overjoyed to see Cavill stepping back into the role of Superman. Though the cameo potentially sets up Superman facing off against Black Adam in future DC films, Superman's cameo in The Flash might be something more light-hearted. Clark Kent and Barry Allen had a playful relationship in Justice League, with the film even finishing off on the humorous note of the two racing across the United States.