Filming “Mank” while pregnant had its challenges.

In a new Vanity Fair “Cocktail Hour, Live!” conversation with Julianne Moore, the Oscar-nominated actress talked about the experience of shooting the movie while pregnant with her son.

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“I’m so glad because I love my son but I was so ill,” she said. “The weekend before one of the big scenes where actually I don’t have any lines… I thought that it was going to be a little easier [even] knowing that I was going to have to be in the makeup chair at 3:30 [a.m.] on one of the days.”

She added, “I was in bed the whole weekend thinking, I don’t think I can do this. I can’t be sick and working with David Fincher and play Marion Davies at the same time.”

Seyfried also revealed that she kept her pregnancy a secret from everyone on the set except for the costume designer.

“I’m four and a half weeks pregnant, I’m not supposed to say anything but I’m bloated and I can only eat cream cheese!” she laughed.

Seyfried also talked about prepping for her upcoming role as real-life, disgraced businesswoman Elizabeth Holmes.

“I’m not imitating, but I’m capturing the essence that hopefully the audience starts to believe me as her,” the actress said.

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Also during the conversation, Seyfried revealed her middle school obsession with “Dawson’s Creek”.

“I turned into Joey Potter,” she said.