Ben Affleck reportedly replaced Michael Keaton as Batman in Aquaman 2

gamesradar.com:

In the wake of Batgirl being shelved, new details have emerged about Michael Keaton’s return as Batman. The actor, who last played the Dark Knight in 1992, was set to play a role in the upcoming DC adaptation Batgirl ahead of his confirmed appearance in The Flash.

But, those two movies were not going to be his only appearances in the DCEU, according to The Hollywood Reporter (opens in new tab). Keaton also filmed a scene as Batman for the Aquaman sequel, Aquaman and The Lost Kingdom. Although, it's not clear if viewers will ever see the scene after test audiences found his inclusion confusing. 

The major concern seemed to be over why his version of Batman was in the Aquaman universe, almost 20 years on from his last appearance in the role. His return is only set to be explained in The Flash, which is opening after Aquaman 2 in theaters – Aquaman 2 is out on March 17, 2023, while The Flash is released on June 23, 2023.

The test screening responses may also explain why there was a recent confirmation that Ben Affleck is returning as the Caped Crusader in Aquaman 2. Jason Momoa shared the news on Instagram with a snap of the pair on the set of the sequel. The Hollywood Reporter suggests the move could mean Affleck is taking over the scene Keaton filmed for the movie.

The report also indicates Keaton was set to play a regular role in the DCEU as Batman going forward. His character was to act as an advisory figure, similar to that of Samuel L. Jackson’s Nick Fury in the Marvel movies. It’s not clear whether this is still the plan following Batgirl’s axing.

For a list of every Marvel, DC, and comic book movie on its way, check out our guide to the confirmed new superhero movies releasing in 2022 and beyond.