It came without warning, but will be remembered by all who witnessed it as the biggest shocker yet in the world of superhero casting: Ben Affleck landing the part of the Dark Knight in Batman V Superman: Dawn of Justice. One of the most famous men in Hollywood playing Batman used to be no surprise, but following Christopher Nolan's selection of Christian Bale, and Zack Snyder sending Henry Cavill's star on the rise, the casting of an Oscar-winning writer and director was a certified shock.

But according to Charles Roven - producer on Nolan's Dark Knight Trilogy, Man of Steel and Batman V Superman - the new version of Batman required some different features; features that Affleck had in spades. In fact, Affleck fit the part so well, he was at the top of a very - very - short list.

We made a case for why Ben Affleck would be a good fit for Batman/Bruce Wayne when the news first broke, citing his size, experience behind the camera - and in front in his own films - along with the fact that, to this point, the actor has spent a large portion of his life in the public eye. Not to mention the fact that when Cavill stands toe-to-toe with Affleck, he'll be looking up to him in more ways than one.

Speaking in an interview for LMU Film School's Hollywood Masters series, Charles Roven explained that those were largely the same reasons that Snyder, Nolan, and the rest of the creative team liked him for the part - while giving a few more details about what fans can expect:

"We knew that we wanted a very mature Batman, because we wanted to juxtapose him against this young Superman. So we wanted a guy who was tougher, rugged, 'hard life lived' about him, and we wanted the guy to have chops, for sure. So when we went down that list, there just weren't a tremendous number of guys that we felt could carry that.

"We also wanted a guy with big stature. Ben is 6' 4". Henry [Cavill] is 6'1". We wanted Batman to tower over Superman. Not hugely, not like a basketball player. Superman needed to look up to Batman. We wanted that dynamic. And Ben could do that, easily. So we really... he was the first guy we went to. That's who we wanted."

Batman Ben Affleck First Choice Actor

Roven then explained that Affleck's past work on Warner Bros. films meant he was no stranger to their group, and Affleck's praise for WB as a whole also explains why he became a prime candidate. Some might claim that having a few inches or pounds on Superman may not matter when the two come to blows, but those following the film closely know that Affleck also wasn't immediately eager to jump into the ring with DC's most famous characters.

At the time of his casting, the actor/writer/director claimed that he agreed to play the part only after he understood just how different his version of Batman would be from Christian Bale's. Roven reiterates that same sequence of events, adding a tease at how Bruce Wayne's personality will be very different this time around:

"I wouldn't say he hesitated. I think that what he did do was that he made sure that he understood what Zack was looking for... he wanted to know exactly how Zack planned on treating this Bruce Wayne that was going to make him be completely different even though he was still Bruce Wayne, still Batman...

"He's a much more social animal in the Bruce Wayne incarnation, but he's also an extremely rough guy in the Batman incarnation. Very, very, very, very rough."

Comic book fans will be pleased to hear those words, as Bruce Wayne's 'playboy' reputation and persona are persistent elements of almost every comic incarnation. A taste of that double life was given briefly in Batman Begins, and later in The Dark Knight, but Bruce Wayne was far from a 'social butterfly' in either story.

So even if Batman's age in Dawn of Justice and the clear influences taken from Frank Miller's "The Dark Knight Returns" suggest a radical shift, Roven's description here implies that Bruce could still be the charming socialite audiences were previously familiar with. Even if he is a bit grittier than they're used to seeing.

Ben Affleck talks Bruce Wayne's anger in Batman V Superman

Does a blend of the old, grizzled, and "very, very, very rough" Batman and the more social, charismatic Bruce Wayne seem like a mix that would do well in DC's shared movie universe? Do you still have reservations about Affleck's fit in the part, or does the knowledge that Snyder saw him as the perfect actor for his new vision calm some of your concerns? Sound off in the comments.

Batman V Superman: Dawn of Justice arrives on March 25th, 2016.

Follow me on Twitter @andrew_dyce for Batman V Superman updates as well as movie, TV, and gaming news.

Source: LMU Film School (via THR)