It was a secret, but Kaley Cuoco was kicking butt for two.

In “Role Play," the actress returns to the kind of production she loves. The kind that continuously flips between thriller and dark comedy – think Max’s “The Flight Attendant” and Peacock’s “Based on a True Story,” which has been greenlit for a second season. And she was pregnant during filming.

“I told my stunt double, and I told my makeup artist, and I told (my partner) Tom – maybe not in that order,” Cuoco says laughing. The "Big Bang Theory" alum became a mom in March when she and actor Tom Pelphrey welcomed daughter Matilda. “It was, like, Week One that we were there. I was there (in Germany) a few weeks early to do stunt training and that's when I found out, and I was like, ‘Oh God.’ So I basically spent that entire film very, very ill.”

"Role Play," streaming on Prime Video on Friday, has Cuoco portraying Anna, an assassin who long-ago adopted the moniker Emma and conceals her day job from loving husband Dave (David Oyelowo) and their two children. Anna taps into her ability to disguise herself while carrying out her kills for a night of role-play when she forgets her and Dave’s anniversary. Chaos ensues when Anna’s work begins bleeding into her personal life, starting with her romantic night gone awry.

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“She’s tough; she’s secretive. But at the end of the day, she's a wife and a mom, and I think that's actually the most important thing to her,” the 38-year-old says.

Cuoco decided to keep her bundle of joy under wraps out of fear she wouldn’t be allowed to take part in the stunts and action that drew her to the role. “I didn't want anyone to worry, and then I knew they'd be overly protective,” she says.

She broke the news to Oyelowo after a hotel they filmed in made her so nauseous she repeatedly inhaled lavender spray on a tissue to keep from throwing up. “I had to tell him because I didn't want him to think I was just this crazy, weirdly smelling, annoyed human being because he didn't know me any other way,” she says with a laugh. “He's such a family man and has four beautiful kids. He was so excited for me.”

Cuoco’s stunt double Monette Moio, one of the actress’ dearest friends, pushed her way into the more dangerous stunts so Cuoco could maintain her secret.

“They’d go, ‘Hey, Kaley, can you fall down this ditch and do, like, seven rolls and then get up and then run with this giant gun?’” Cuoco remembers. “And Monette would go, ‘No, no, no, she can't! I’ll do that.’

“But I ended up doing a lot on my own,” Cuoco adds, much to the dismay of the film’s stunt coordinator, who she shared her pregnancy news with on the day the movie wrapped.

“He was so shocked and mad at me – fake mad at me,” she says. “But he was like, ‘What?’ I mean, I'd fallen into glass tables. I was doing so much stuff.”

Cuoco hopes her falling into a glass stunt table, an unplanned move, impresses Matilda one day.

“I think she's going to think it's so cool, and I can't wait,” Cuoco says. “We're a very powerful house, and I want her to know that she can be anything she wants to be, and she can do it all at once, the way that a lot of women do.”

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