How Viola Davis and The Woman King Cast 'Became Warriors' Through Intense Training

How Viola Davis and The Woman King Cast 'Became Warriors' Through Intense Training

The female-led cast for The Woman King spent months preparing in order to make the action-packed film come to life.

In this exclusive behind-the-scenes video, the stars explain the sweat and hard work that went into becoming warriors. Gabriela Mclain, cast trainer and nutritionist, spoke to PEOPLE and detailed the intense workout plan and how she felt empowered by the women on set.

"My goal was to pretty much make it natural, just as the woman would look if they were to go and fight because it's based on true stories. I'm trying to stay authentic, even with the body," she says. "There's all kinds of enhancers you can take to get lean and ripped and all that, but I did not want them to look like Miss Olympia, I tried to stay authentic so they look like warriors."

Mclain worked directly with Viola Davis, Thuso Mbedu, Lashana Lynch, Sheila Atim and Adrienne Warren. Training for the film lasted about nine months and McLain had the stars working out with her for three hours every day.

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The upcoming historical action drama also stars Hero Fiennes Tiffin and John Boyega and is the story of the Agojie, an all-female unit of warriors who protected the African Kingdom of Dahomey in the 1800s.

RELATED: See Viola Davis Go to War in Action-Packed 'The Woman King' Trailer

Because the actresses had days "full of movement" on set, Mclain says she focused on functional fitness with strength training, weightlifting, sprinting and high intensity workouts to build endurance and stamina. The stars also had two hours of weapons training with their stunt coordinator Danny Hernandez, so Mclain would analyze the martial arts movements in order to create a workout plan to help improve their strength.

"Before we started I actually did DNA testing on the main five that were signed under me, which was Viola, Thuso, Lashana, Sheila, and Adrienne. I did the DNA testing on all of them, which helped me pretty much figure out the best way to train, the best way to protect their muscles and protect their body because they're all different," she says. "There's no one plan fits all. Everybody needs to train in a different way."

THE WOMAN KING - Viola Davis
THE WOMAN KING - Viola Davis

Sony Pictures

Mclain says the actresses were also under a strict nutritional plan, but were eating more rather than cutting back in order to bulk up.

"I did not want them to lose too much weight, I wanted them to gain muscle," she explains. "So they were eating five meals a day, every three hours. They had to drink one gallon of water a day and each of them had a different nutritional plan, which I designed."

In the clip, Viola Davis says she felt "like a bad ass" after getting through her intense physical transformation.

"When I was a girl wanting to win the Miss Central Falls Recreation Contest — wanting to look good in a bikini, wanting to be thin and cute and delicate and pretty — I just wanted to be willowy and thin. I was always muscular and thicker, and I felt like my femininity could not be created with this canvas. And then all of a sudden, with this role, my muscles, my arms, my thick legs, my heavy voice were perfect. I felt unapologetic about it. I celebrated it physically in every way," Davis tells PEOPLE. "Sometimes you do a movie and then it's over. And sometimes, you do a movie and it shifts you a little bit. You're a little bit better for it. And that's what it's been like for me with the training."

Mclain praises the women for the ability to "become warriors" in a short amount of time and feels a sense of pride and "empowerment" by helping them through the process.

"Every training, they never gave me attitude, I never had to drag them. They actually wanted to do it and sometimes they would even ask me for more training because they saw the results and how much the hard work paid off," Mclain adds. "Seeing them transform, it was amazing. I was so proud standing there with tears in my eyes."

RELATED: 'Biggest Loser' Trainer Erica Lugo Is Down 30 Lbs. as She Preps for Her First Fitness Competition

THE WOMAN KING - Viola Davis
THE WOMAN KING - Viola Davis

Sony Pictures

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"They all literally blow my mind. They really put their heart and soul into this," she says. "These women literally worked their butts off and everything you're gonna see on that screen is real, 100%. Their skills, their body, every member of the cast; it's just real and it's earned."

The Woman King will release exclusively to movie theaters on Sept. 16.