Kaley Cuoco and David Oyelowo reveal how they made Role Play with 'B.O., nausea, and tuna sandwiches'

Kaley Cuoco was, appropriately, living a double life while filming Role Play.

The Flight Attendant star plays notorious international assassin Emma in Prime Video's new comedic action movie (streaming now) opposite David Oyelowo, who plays her unsuspecting husband David, whose entire world shatters when he learns his wife's deadly secret. While the actors were in Germany making the movie, Cuoco was keeping a massive secret from her onscreen counterpart — and everyone else in the cast and crew as well.

"I found out I was pregnant while we were shooting, and I was definitely keeping that secret," Cuoco tells EW. "I actually wanted to tell everyone because I was so excited, but I've always wanted to do some sort of action — I felt like that's my calling in life — and they would've freaked out and taken all my stunts away."

In fact, the only person Cuoco told her secret to was her stunt double, Monette Moio. She's not only one of Cuoco's best friends, but she was able to step in when there were moves the Big Bang Theory alum couldn't physically do while pregnant. "It was very funny if they would say something like, 'Can you somersault over here, and then flip ... ' whatever they were asking, and Mo, would say, 'Oh, no, she can't do that. I'm going to be doing that,'" Cuoco says with a laugh. "She kept interjecting and I think they thought she was so crazy protective of me. Then on the last day of filming, I went up to our stunt coordinator and told him that I was pregnant and the look on his face — oh, man, it was so worth keeping it from him."

Cuoco clued her costar Oyelowo in on her secret earlier, about halfway through filming, because he was starting to realize something was up with her. "Kaley was acting so bizarrely at points — she had this hypersensitivity to smell, she would have this 100-yard stare every now and again," Oyelowo tells EW. "I'd thought, 'Are my stories not entertaining you? Are we okay?'"

He laughs before revealing that she eventually told him while they were filming a scene in Emma and David's bedroom. "We were lying in bed together, and she just said, 'I'm pregnant,'" he says. "I'm such a lover of babies, so I just found myself welling up. I started crying in the scene where it was incredibly inappropriate to be crying. It's funny, now that I think of it, Kaley, that scene is not in the film. We probably ruined that scene with my tears."

"Well, I'm known for my timing, so the fact that I told you right then was so ridiculous," Cuoco responds, the laughs continuing. "It was a day where I was really out of my mind with the smell, and so I had to say something. Also, I love David so much that I didn't want him to leave this film being like, 'There are moments that Kaley was genuinely bizarre.' David is the most incredible family man I've ever met, so I knew he was going to be the biggest fan for me to tell him. He was like a little kid when he heard."

The topic of smell comes up a lot for Cuoco and Oyelowo, because it turns out that the Role Play set didn't always smell, well...good, to put it lightly. "Gosh, I already know I'm going to regret saying this but I just have to tell the truth: We shot in Germany, and my most challenging day on set was an incredibly hot day, and we were shooting in an attic, a perfect circumstance under which heat gathers and just sits in there," Oyelowo says. "We had a very male-heavy crew, a lot of who, for whatever reason, had not been introduced to deodorant. It was so thick in there, you could virtually taste it."

And with Cuoco's heightened sense of smell due to her pregnancy, it's a day she'll never forget. "He's right — they just did not wear deodorant," she says with a laugh. "But my worst day was, we were shooting the scene where we're going to bed early in the film and the kids yell, and I was the sickest I have ever been in my life, nausea that entire day. I was so ill. When I watch that scene, oh my God, I look like I am dying. I'm actually surprised they didn't reshoot it because I look like a different person."

"That's why she had to tell me she was pregnant," Oyelowo adds. "But I just thought that was brilliant acting, Kaley. I didn't realize you were just having a terrible moment there."

"Unfortunately, I'm not that good," Cuoco quips.

She's being incredibly facetious because Role Play allows Cuoco to show a much different side to her acting than ever before as the deadly, ruthless Emma. "I'm usually the one being cheeky, and I had more of a grounded character than normal," she says. "And David is such a brilliant dramatic actor, and to see him be cheeky in this is so enjoyable and surprising. As people, I'm a little up there and David is so grounded, so we, in life and in the film as characters, swapped, which was awesome. And we also loved the gender identity swap."

She's referring to the fact that historically in films of this genre, the man is the notorious international assassin, while the wife is the one to discover her husband's secret and get thrown into the mission for which she's unprepared. But Role Play takes that idea and flips it on its head.

"That's exactly why I felt that this was extra special because we've seen beloved films like True Lies or Mr. & Mrs. Smith, but this literal role reversal when it came to the gender norms was something that I just found very interesting," Oyelowo says. "What I liked is the fact that David still has this misguided notion that he's a man's man, he's going to save the day, and completely underestimates who his wife is and what she actually does. He has to realize the fact that those roles are swapped, in that it's his wife who really knows her way around getting them out of these sticky situations. It just brings a fresh take to something that is familiar."

That idea is what first attracted both actors to this movie. Cuoco signed on first years ago, and when Oyelowo became interested in playing her husband, they went to lunch together to get to know each other. And Cuoco was determined to make that lunch count.

"She presented me with 20 random questions out of the gate, written down, that I had to answer — like whether or not I like mushrooms, whether or not I like goats, whether or not I like to wear socks indoors or not," Oyelowo says with a laugh. "We got to know each other very, very quickly."

"Look, we've all been on these outings where you're meeting potential costars, and it's like a strange blind actor date. It could be very awkward," Cuoco adds. "I wanted this to go so well, and it was such a big deal that he even read the script and was considering this, so I was like, 'Don't mess this up. How can I make this fun?' I just started thinking of all these questions I genuinely wanted to know, questions that mean a lot to me as an animal lover, as a mushroom hater."

Those 20 questions worked "brilliantly," the actors agree. "It opened conversations, and we were immediately laughing because the answers were so funny," Cuoco says. "We were like, 'Wow, I feel like I know you better than I know half my friends that I've known for 20 years,' so it just set everything off on the right foot."

There is another meal that both Cuoco and Oyelowo will never forget, one that included their Role Play costar Bill Nighy, who plays someone from Emma's spy life who comes into contact with David and threatens to expose her secret.

"I only wanted Taco Bell and Subway the entire time we shot, and Germany did not have Taco Bell, so I had to live with Subway — it was my secret because eating a Subway tuna sandwich in 100 degrees on a stage with men not wearing deodorant is probably the grossest thing you could do," Cuoco says. "So I would secretly eat these tuna sandwiches, and then I found out that Bill's favorite thing is the tuna sandwich from Subway."

When Cuoco discovered she and Nighy both shared a love of the same Subway tuna sandwich, she invited him to have a lunch date with her. "He was like, 'That sounds amazing,' so we had, in his dressing room, Subway tuna sandwiches, and it is genuinely a memory I will never forget," she says.

"But she then sent me a picture of her and Bill having this lovely cheeky lunch to which I wasn't invited," Oyelowo adds. "I was just like, 'Oh, wow, Bill, come in and just steal my costar. What am I here? A third wheel in my own movie marriage?' I was filled with both delight and envy when she sent me that photograph. Every time I go past a Subway now, I remember."

Cuoco laughs as she says, "Yeah, you'll never forget."

"B.O., nausea, and tuna sandwiches: That sums up Role Play," Oyelowo says.

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