Karen Gillan says 'Gunpowder Milkshake' had the 'most intense' action training she's undergone (exclusive)

Watch: Karen Gillen talks to Yahoo about Gunpowder Milkshake

Karen Gillan has made a name for herself in action roles.

Playing Nebula in the Guardians Of The Galaxy and Martha in the Jumanji sequels have tested her physical mettle. But it all comes to an explosive climax in her latest movie Gunpowder Milkshake – in cinemas and on Sky Cinema from 17 September – which she describes as "definitely the most intense I’ve had to do in terms of training".

Talking to Yahoo, she revealed she had less than a month to get herself in shape for her kickass lead role in the film.

“I’ve done action sequences in other films, but nothing where it’s non-stop action from start to finish," Gillan tells us.

"I only had three weeks to get ready, so those weeks were like action hero boot camp.

“I’d arrive in the morning and work with my stunt double, Aurelia [Agel], who is the fittest 21-year-old you’ll ever meet in your life.

Read more: 'Nebula's story has only just begun,' says Gillan

“And I’d be running around the studio with her and she’d be teaching me boxing. Then we’d do loads of stretches and warmups and then we’d start learning the fight choreography.

"And we’d do that for hours, starting in slow motion and then picking up the pace until we could go flat out at 110%!”

Agel was also Scarlett Johansson’s stunt double in Black Widow.

Gillan needed every ounce of that training and Agel’s expertise for her high-octane performance as an elite hitwoman who follows in the footsteps of her mother (Lena Headey) by cleaning up the most dangerous messes confronting a ruthless crime syndicate.

But a failed high-risk job turns her into a target, and her only chance of survival is reuniting with her mother and her trio of deadly associates, known as The Librarians, to stand up to the henchmen.

Watch a trailer for Gunpowder Milkshake

The action comes thick and fast in the movie, but Gillan describes the very first sequence as the toughest to pull off, because “it’s the first time you see her fight. There’s a long buildup to it, people are saying things like ‘remember who you’re dealing with’, so it had better be bloody good!”

Read more: Karen Gillan wants to redo her Doctor Who performance

And she recalls that director Navot Papushado had a very specific vision for the scene.

She says: “He wanted it to be all one take, a tracking shot and a wide shot, so you can see all of the choreography with no cut points to hide behind. Normally, they can chop it up to look exciting but there was nowhere to hide on this one: only actors, no stunt doubles.”

Co-star Lena Headey, who plays her mum, helped provide some light relief from all the strenuous physical activity. Gillan and the Game Of Thrones star shared an instant connection.

“We started talking and realised we had a lot of similarities – we enjoy silly Instagram videos, for instance! There was so much laughter pretty much straight away and we shot a movie in between all of those silly videos!”

Completing the film’s powerful female line-up alongside Gillan and Headey are Michelle Yeoh (currently in Shang-Chi And The Legend Of The Ten Rings), Angela Bassett (Black Panther) and Carla Gugino (The Haunting Of Hill House).

Gunpowder Milkshake is in cinemas and on Sky Cinema from 17 September.