With just over a month to go until the movie's release, Batman actor Ben Affleck is revealing what went into creating Batman v Superman's caped crusader.

In an interview with Good Morning America, Affleck said that he trained for a year and put on about 20 pounds of muscle to play Bruce Wayne. He went on to discuss the pressure to live up to fans' massive expectations, but he said he's ultimately happy with the finished product. Besides, Affleck received some helpful words of wisdom from previous Batman actors.

"I talked to Clooney. He had some advice which was not repeatable," Affleck said. "And I talked to [Christian Bale], who just told me to make sure I got a zipper in the suit, which was valuable, practical advice as it turned out."

Both Affleck and Superman actor Henry Cavill answered the question a lot of viewers probably asked upon hearing the premise of Batman v Superman: How is a battle between an indestructible alien and a rich dude without any powers a fair fight? Basically, it's not.

"[The movie] takes advantage of the fact that Superman's a good guy and probably wouldn't just pull his head off right at the beginning," Affleck joked.

Cavill and Affleck are obviously both hopeful that the movie will do well, although the studio is apparently feeling some anxiety. A new rumor suggests that Warner Bros. is nervous that Dawn of Justice won't perform well and that they may have to retool their upcoming slate of films as a result, as we previously reported.

Batman v Superman: Dawn of Justice opens on March 25.