Nicole Kidman Jokes About 'Throuple' With 'Bombshell' Co-Stars Charlize Theron, Margot Robbie

Nicole Kidman, Charlize Theron and Margot Robbie are all starring in the upcoming film Bombshell, which tells the story of the women of Fox News who stared down former CEO and chairman Roger Ailes and ultimately got him fired from the network. Kidman will play Gretchen Carlson, Theron stars as Megyn Kelly and Robbie plays composite character Kayla Pospisil.

During separate interviews with Entertainment Tonight, Kidman and Theron joked about the relationships they had developed with her co-stars while making the movie, with Theron the women her "girl crushes" when asked. She also joked that they are a "throuple," a three-person couple, a claim Kidman gamely echoed.

"Oh yeah, I knew," the Oscar winner joked. "It's been going on for so long. We're the best secret keepers in the world. Threesome, yeah!"

Kidman also discussed the film itself and praised Theron for her integral role in getting the production off the ground.

"This film is a very powerful film… and Charlize really sort of championed getting it made," she said. "So when Margot and I came in, we went, "Yeah, of course, we want to be there, we want to support you. We want to get this thing made.'"

"I think it's an important story," Theron told ET last year. "It was written really well, and I think it was the writing, and the filmmaker, that made me realize it was in the right hands. We need to tell these stories, for sure."

In addition to Kidman, Theron and Robbie, the film stars John Lithgow as Ailes, Allison Janney as Ailes' legal counsel Susan Estrich, Alice Eve as Fox & Friends co-host Ainsley Earhardt, Alanna Ubach as Justice With Judge Jeanine host Jeanine Pirro, Mark Duplass as novelist Douglas Brunt and Malcolm McDowell as media mogul Rupert Murdoch.

Speaking to Entertainment Weekly, Carlson admitted that it's "frustrating" she can't be part of the projects documenting her life, which also include a Showtime miniseries staring Naomi Watts.

"It's a strange and frustrating reality that I can't partake in any of these projects based on my settlement, which is why I'm working so hard on Capitol Hill so that nobody else has to be handcuffed anymore," she said. "In the end, I can't participate, but it's all about continuing the dialogue. And if projects like this and the Showtime miniseries keeps people in our society talking about this issue, then that is amazing. And most importantly, if it gives courage to men and women who are facing these kinds of situations to come forward, then that's the extra bonus."

Bombshell premieres in theaters on Dec. 20.

Photo Credit: Getty / Dia Dipasupil