The Woman King is an upcoming historical epic starring Viola Davis in the leading role. Directed by Gina Prince-Bythewood, the film is about an all-women legion of warriors who are tasked with protecting and defending the Kingdom of Dahomey in West Africa in the 19th Century. The Woman King is set to have its world premiere at this year's Toronto International Film Festival, before releasing in theaters on September 16.

Davis stars as General Nanisca, and you can already see her kicking butt in The Woman King's trailer. What's more, Davis has remarked on her "transformative" role in the film, which required a great of physical and emotional exertion. Indeed, the actress had to undergo specialized training to get into the body and mind of General Nanisca. Here's how Davis prepared for her role in The Woman King.

Davis Followed an Intense Workout Routine

Viola Davis as General Nanisca
Sony Pictures Releasing

David had to do a lot of physical training to prepare for her role and packed on a lot of muscle to play the role of Nanisca. In a training featurette with CNN, she spoke about how the process made her feel unapologetic about her body and allowed her to celebrate the physical beauty of a muscular frame and how its relation to femininity. Davis had to embark on an intense journey to get her body ready for the physically demanding role. The routine was constructed by her trainer, Gabriela Mclain, and it involved high-intensity exercises, including sprinting and weightlifting, which would put her body through incredible challenges and totally transform her physique (as outlined by Women's Health). Her trainer also worked with Davis' The Woman King co-star Thuso Mbedu, Lashana Lynch, Sheila Atim, and Adrienne Warren, and the routine clearly paid off.

Related: These Are Viola Davis' Best Performances, Ranked

She Trained With Weapons

the woman king
Sony Pictures Releasing

One of the most intense aspects of Davis’ training regime for The Woman King was using weapons in her routines in order to prepare her for the scenes that would involve her character wielding weapons to defend herself. She went through nine months of training, and learned martial arts involving swords, spears, and machetes. It would be easy to allow this work to be done by a stunt double, but Davis underwent a vigorous process to ensure she was fully prepared for her role and could perform her own stunts and fight choreography in the film.

Related: Here's a First Look of Viola Davis in The Woman King

Viola Kept to a Strict Diet

Viola Davis in The Woman King
Sony Pictures Releasing

Mclain was responsible for the physical transformation of Davis, and the process took months and was grueling on Davis, both emotionally and physically. Her workout regime was relentless and was specifically curated to transform her body as much as possible in a relatively short amount of time prior to filming. Alongside the intense physical process involved, Davis also had to totally transform her diet and followed a strict nutritional plan. She had to bulk up rather than cut down and had to make sure to drink a gallon of water a day, as well as consume five balanced meals.

Her Trainer Used DNA Testing

Viola Davis in The Woman King
Sony Pictures Releasing

One of the unique things about the training process that Davis underwent for The Woman King was that her trainer used DNA testing to specifically tailor dieting and training programs to help each actor excel the best that they could on their fitness journey. This is an extreme measure that is becoming more common in personal training, tailoring results to clients and their specific needs, and ultimately finding what works best for individual bodies. The efficacy of these tests have been backed up by publications, such as Men’s Health, however, others are unsure of how effective these can be. The plan clearly worked in Davis' case, and the intense workout and diet regime yielded amazing results that we can’t wait to see on screen when The Woman King hits theaters.