During a conversation with Cillian Murphy, Margot Robbie revealed that a producer for "Oppenheimer" tried to convince her to move the opening date for "Barbie."

The two actors interviewed each other as part of Variety's series "Actors on Actors," in a story published Tuesday. The duo, who played the titular characters in their blockbuster films, discussed sharing the bill this summer in what would soon become known as the viral "Barbenheimer" phenomenon.

On July 21, both films were released in theaters, but not everyone was a fan of the idea, said Robbie.

"One of your producers, Chuck Roven, called me, because we worked together on some other projects. And he was like, 'I think you guys should move your date,'" Robbie, who co-produced "Barbie," told Murphy. "And I was like, '... If you're scared to be up against us, then you move your date.'"

"And he's like, '... I just think it'd be better for you to move,' "Robbie, 33, says Roven told her. "And I was like, 'We're not moving!'"

The "Birds of Prey" actress thought the double feature was the "perfect pairing."

"That was a good instinct," Murphy, 47, added.

"Clearly the world agreed. Thank God," Robbie responded. "I was like, 'See? People like everything.' People are weird."

The "Inception" actor said the success of both films was ultimately up to the public. "They don't like being told what to do," Murphy said. "They will decide, and they will generate the interest themselves."

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Robbie also attributed both films doing well to their directors. "People were itching for the next Chris Nolan film and itching for the next Greta Gerwig film," she said. "To get them at the same time was exciting."

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The actors talked about working with their respective directors and preparing for their roles, with Robbie admitting that getting into the role of the iconic doll was difficult at first.

"I rely on animal work a lot," she said of one of the tools she used to try to prepare for the role. "I was maybe 45 minutes into pretending to be a flamingo or whatever, and I was suddenly like, 'It's not working.'"

"I went to Greta, like, 'Help me. I don't know where to start with this character,'" she said.

After some back and forth, with Robbie asserting she wanted her character to appear "naive" but not "dumb and ditzy," Gerwig suggested an episode of the "This American Life" podcast about a woman with no inner voice.

"This woman's got a Ph.D. and is extremely smart, but just doesn't have that internal monologue," she said. "She kind of thinks about exactly what's in front of her — a spotlight to what exactly is in front of her at the time."

"Oppenheimer" recently crossed $950 million in earnings, while "Barbie" became the highest-grossing film of 2023 — and Warner Bros.' biggest movie ever — at more than $1.44 billion worldwide.

"Barbie" also broke a record for female directors that was previously held by Patty Jenkins, who helmed "Wonder Woman."

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