Lena Headey's new film Gunpowder Milkshake is an R-rated action flick

Timed perfectly to punctuate the halfway mark of the school holidays, there's a reason for parents to book the babysitter and go to the movies for an R-rated action flick.

It's called Gunpowder Milkshake and stars Game of Throne's actor Lena Headey.

Lena Headey will forever be embedded into pop culture legend as Cersei Lannister in the game-changer that was Game of Thrones.

The mammoth show was a full-time job for years and its epic finale signalled her release back into the wild and onto the big screen.

The wrestling film Fighting with my Family turned out to be the perfect training camp for her latest movie here. She's definitely still fighting with her family - this time her estranged daughter in Gunpowder Milkshake.

"I love a bit of action. Any chance to work with a stunt team, the tomboy in me is thrilled," Headey tells Newshub.

Shooting a one-off two-hour movie was also a big change of pace after so many years buried in the wilds of Westeros.

"Sometimes those one night stands are rewarding in a different way," Headey says.

So when it came to inspiration for the gun-totting knife-throwing body-counting mother figure Scarlett?

"My only sort of reference point for Scarlett was a violent Mary Poppins," Headey says.

She plays a rather ruthless assassin and a fairly unorthodox mother to Karen Gillan's Sam who ends up following in her mother's bloodsoaked footsteps.

Clearly, this one's not for the kids - shock horror - but is rich in sisterhood and sticking it to the man, so to speak.

And alongside such a stellar cast of women Headey was in her happy place.

"I have to say without sounding totally cheesy or that we're on a publicity thing right now… but there was an immediate sisterhood vibe, just a celebration of who everybody was," Headey says.

"It was really a great working environment, I loved every minute of it."

Gunpowder Milkshake is currently being served up at your nearest cinema.