Henry Cavill has already filmed the Superman cameo for The Flash movie.
Cavill debuted in the DC universe as Superman in the movie The Man of Steel in 2013. Before Cavill appeared in the post-credits sequence of Black Adam this year, his future as Superman was uncertain for a number of years.
The new CEOs of the DC Studios James Gunn and Peter Safran have come up with the eight to ten year future plan for the DC studios. The new CEOs have removed a lot of franchises and have made some changes in the studios.
According to the Hollywood Reporter, Cavill has reportedly already shot a cameo as Superman in The Flash. Jason Momoa’s Aquaman is also anticipated to make a brief cameo appearance. Cavill has shot his role back in September.
For now nothing has been finalized yet regarding whether Cavill’s cameo will be included in The Flash’s final edit as of yet. Despite the current uncertainty surrounding the Justice League, DC has full intentions of releasing The Flash. Given that Cavill’s Black Adam cameo was published before Gunn and Safran assumed control of the franchise, the appearance isn’t a guarantee that Cavill will stay a part of the DCU, especially in light of all the rumoured upcoming changes to the series.