Speaking on Jimmy Kimmel’s talkshow last night, the actor – who is playing the part for the third time in the new DC caper – said it was all to do with impressing his young son.
However, it seems that may have backfired slightly.
He opened up: “Literally the reason I took this movie is imagining wearing that costume and having my little boy see me.
“Everyone wants their kid to think of their son as a superhero, before they get too smart!”
However, he added: “I brought in a picture which is my son two weeks ago.
“Which was, ‘dad, there’s on costume I want in the whole wide world, can you get it?’
“And I said, ‘you know, I have some connections!’ And then he told me who he wanted to be.”
When Kimmel held up the picture, it seemed it was not Batman that Affleck’s son was idolising… but the Flash, played by Ezra Miller.
Early reactions to Justice League have been generally positive, with social media posts praising the fun nature of the movie and the strong characters, but criticising the plot.
The film follows the acclaimed Wonder Woman, which came out earlier this year.
Justice League is out on Friday.