The actress — who has been cast as the caped crusader’s adoptive mother Martha Kent in the upcoming film — says she was locked in a room with the script for three hours to ensure the plot remains a secret — but still revealed that Superman’s origins will be covered.
“I read the script under lock and key. I was locked in a room with the script and was only allowed three hours with it. I nailed it into my memory. I’m really excited,” Diane explained.
“I’m really not allowed to talk much about it, I think, but it does cover the entire range of years, from infancy on.”
The brunette beauty is set to star alongside Henry Cavill in the movie which is being directed by Zack Snyder.
Diane — who raises 17-year-old daughter Eleanor with husband Josh Brolin — recently insisted that “willing to be wrong” makes her marriage work.
“It’s staying grateful, humble, willing to be wrong and thinking about the other person at least as much as you think about yourself,” she said.
“Put yourself in the other person’s moccasins, you know?”