“There are certain characters who hold a special place in the hearts of millions," Affleck said in a statement. "Performing this role demands focus, passion and the very best performance I can give. It has become clear that I cannot do both jobs to the level they require. Together with the studio, I have decided to find a partner in a director who will collaborate with me on this massive film. I am still in this, and we are making it, but we are currently looking for a director. I remain extremely committed to this project, and look forward to bringing this to life for fans around the world."

The move has been in the works for several weeks now, according to a source.

"Warner Bros. fully supports Ben Affleck's decision and remains committed to working with him to bring a standalone Batman picture to life," the studio said in a statement.

Insiders say that Affleck and the studio came to a mutual decision that it would be best for the project if it was not helmed by someone with the split focus of being both the star and helmer.

One insider says that Live by Night's poor performance caused Affleck to rethink his approach to his projects after that film bombed recently, having taken in just $18.9 million globally to date.

No release date had been set for the Batman movie, which also is set to star Joe Manganiello as the villain Deathstroke. But the film has been seen as a key part of Warner Bros.' DC strategy, so much so that it had been prioritized over a Justice League sequel.

So far, Affleck has played the Dark Knight in last year's Batman v. Superman: Dawn of Justice and Suicide Squad. He next will appear in November's DC superhero team-up movie Justice League.