The Oscar-winning actress stars as Queen Atlanna in the upcoming film Aquaman, starring Jason Momoa as the titular superhero. ET's Kevin Frazier caught up with Kidman, 51, during the Warner Bros. and DC press line on Saturday, where she shared the flattering way that the movie's director, James Wan, convinced her to join the cast.
"It's so funny because James said to me, 'I so want you to do this,'" Kidman told ET. "And he said, 'I'll prove to you that I've always wanted you to do this. In all of my renderings, I drew you. So what're you going to say?'"
Wan used Kidman's face in the film's concept art of the Atlantean matriarch because he had wanted her for the role.
Naturally, the Australian-born star couldn't help but jump at the chance to play a powerful mermaid. Kidman, however, is no stranger to superhero films, having starred in 1995's Batman Forever as Dr. Chase Meridian. During the Hall H panel earlier in the day at Comic-Con, where a new Aquaman trailer was revealed, she also playfully joked about her stunts in the movie.
"My opening shot in the film is being washed up on a rock, and I got to lie there with massive waves washing over me," she shared. "And I kept thinking, ‘Come on, James! Give it to me! The bigger the better! This is why I’m doing this movie!’”
Kidman, meanwhile, has been enjoying her time at the convention, telling ET that her experience has been "amazing," and adding, "It's my first one." Her time at Comic-Con will be short, though, as she has to get back to the set of Big Little Lies.
"I have to be at work tomorrow. I have to do rehearsal and then I have to be back on the set of Big Little Lies on Monday," she explained. "And being the professional that I am, I [have] to leave this afternoon so that I can prep."
The second season of the hit HBO series also includes Meryl Streep, whom Kidman called an "empress."
"I bow down. She's the empress," Kidman said with a laugh. "We go out and we love eating Italian food in Monterey," she added.
Meanwhile, ET caught up with Kidman's Aquaman co-star Amber Heard earlier this year, when she gushed about working opposite "beautiful and soulful" Kidman. Watch the video to hear more.