James Gunn says that controversial Superman lore change was because he allowed himself "to make changes where changes might work" and be "interesting for the DCU"

Superman is a pretty faithful adaptation of Big Blue, with one major exception – Clark Kent's biological father Jor-El is revealed to have a sinister agenda for planet Earth.

As revealed midway through the movie, after Lex Luthor gets his hands on a holographic message from Jor-El and Lara-El that accompanied Clark to Earth, it turns out that Jor-El sent his son to subjugate the planet and its people, completely unbeknownst to Clark himself. Usually, Jor-El's mission is the complete opposite.

"I'm a huge Superman fan, so first of all I had to trust myself that I was going to honor the pieces of Superman that we needed to keep the same," Gunn explained of the change to IGN. "And also allow myself to make changes where changes might work and wouldn't go against the integrity of who the character is. And so I think that was [...] simply dealing with allowing ourselves to change part of the story in a way that was interesting for the DCU, but that wasn't [something] that went against who Superman was. And has been something that's been played with in the comics before."

In the movie, Jor-El is played by Guardians of the Galaxy star Bradley Cooper, in one of the surprise Superman cameos and Easter eggs. Gunn has also explained why Cooper was the right choice for the role, which has previously been played by the likes of Marlon Brando and Russell Crowe.

"I needed somebody who could play Jor-El… who had the stature of what we imagine that character being," Gunn commented. "Somebody who could walk in the footsteps of Marlon Brando."

Superman is in theaters now. For more on the movie, check out our Superman review for our verdict on the DCU Chapter One: Gods and Monsters movie, or dive deep into our breakdown of the Superman ending explained.