"When I heard there was someone else doing it, there was a moment where I just stopped and stared into nothing for half an hour," Christian told Empire magazine.
Christian Bale felt 'jealous' when he learned Ben Affleck had been cast as Batman
"But I'm 40. The fact that I'm jealous of someone else playing Batman… I think I should have gotten over it by now."
Christian put those initial feelings to one side, and revealed he has since reached out to the American actor.
"I haven't spoken with Ben, but I emailed him offering bits of advice that I learned the hard way," he said. "I would imagine that he is doing everything he can to avoid anything that I did."
Ben Affleck will appear in Batman v Superman alongside Henry Cavill
Ben is currently filming Batman v Superman: Dawn of Justice in Detroit, alongside Henry Cavill as Superman, Gal Gadot as Wonder Woman, Amy Adams as Lois Lane and Jesse Eisenberg as Lex Luthor.
Christian, meanwhile, is next set to appear in the biblical epic Exodus: Gods and Kings, scheduled for release on 12 December. He stars as Moses in the film, opposite a cast that includes Aaron Paul, Joel Edgerton, Ben Kingsley and Sigourney Weaver.