The difference in Jyn: How Felicity Jones became a badass for 'Rogue One'

This is a rebellion, isn't it? You need to be in shape to rebel.

As Rogue One's action hero Jyn Erso, Felicity Jones -- an actress formerly known for cerebral dramas like The Theory of Everything -- had to up her exercise game.

"This has been the most physical exercise I've done in my entire life," Jones said in an extra feature in the Rogue One Digital HD package, released Friday.

Director Gareth Edwards shot the Star Wars film documentary style, looking for spontaneous performances. Much of that involved deliberately throwing Jones off-balance to achieve a more natural look when she found her feet again.

In the film, Jyn is more active than even her two main action heroine predecessors, Princess Leia and Rey. The leader of the gang that steals the Death Star plans, Jyn has to attack Stormtroopers and rebels alike, save children from explosions, get blown off platforms and make death-defying leaps.

In preparation for the Rogue One shoot, the 33-year-old hit the gym every day, doing everything from boxing and pilates to swimming, which she credited with toning her arms.

She was then inducted into a multi-week bootcamp with martial arts specialist Liang Yang -- who played the "traitor" stormtrooper that dueled with Finn in The Force Awakens, and who also got martial arts legend Donnie Yen into shape for his role as Chirrut Imwe.

"Felicity's fighting style is direct whereas Chirrut Imwe’s style is flamboyant," Yang told Men's Health. "As we got to understand Felicity’s character, we all decided to make her very strong, powerful and her attacking style very direct."

Result: rebellious badassery.