Christopher Nolan has revealed that creating the world of Superman for Man Of Steel is "far more difficult" than making the world of Batman.
The filmmaker is producing the new blockbuster, due out next summer, while Watchmen's Zack Snyder is directing.
Speaking to the Hollywood Reporter, Chris said: "Zack was the perfect man to take this on.
"He is unbelievably skilled at creating a coherent, cohesive world - whether it's a very stylised world, like 300, or something that's more challenging, more varied, like he did with Watchmen."
He added: "In my honest appraisal, taking on Superman and creating that world is far more difficult than creating the world of the Dark Knight.
"He has a lot of finishing to do on the movie - it has a very long post-production schedule because, unlike Batman, Superman flies.
"I actually feel guilty talking about it because I'm sitting here having nothing to do to it."