“I’m not a gamer per se … I don’t have a life where I can spend hours gaming,” says Natalie Dormer. It’s a bold admission for an actor who has just been revealed as having a starring role in the new Mass Effect game, and one that may not be met kindly by fans of the franchise, but she adds: “I know if I did, this is exactly the kind of thing that I would play.”

Mass Effect: Andromeda, the BioWare title which pairs combat with conversation, should be a good fit for Dormer. She is no stranger to backstabbing, high stakes and court intrigue from her TV work. The characters she plays in the Tudors, the Hunger Games and Game of Thrones are focused, conniving, manipulative. Hard-edged. She swishes silk skirts and allegiances fall; she rises up from the rubble with a shaved head and her fist in the air. To take these traits into the chromed expanse of the Mass Effect universe feels like a logical step. Dormer is voicing a 600-year-old Asari called Lexi T’Perro, one of several aboard the Tempest comprising what she calls “a motley crew”.

Dr Lexi in Mass Effect, played by Natalie Dormer Photograph: EA

The game brings an entirely new cast of characters to join the player in the form of Sara or Scott Ryder: lone-wolf and rogue Asari, Peebee, idealistic human squadmate Liam, veteran warrior Krogan, Nakmor Drack, and others. Dormer tells me that it’s this depth of character that really excited her about the project.

“They’re dependent on each other for survival, tolerant towards each other in their different attributes and strengths and weaknesses that they all bring,” she says. “It even makes me smile, you know, the sexual politics ... there are all these options within the interaction of the characters. It’s so well thought out, and it’s so human, and detailed. It’s to be admired for those things.”

T’Perro is the ship’s physician and psychiatrist, there to guide the player and their crew through the Andromeda universe – similar, perhaps, to Liara T’soni’s role in the original Mass Effect. The Asari were the first race to discover the Mass Relays (which enable faster-than-faster-than-light travel), which makes them the ideal candidate for guiding the player through the Andromeda universe. The all-female race is characterised by their elegance, grace and deadly combat skills. To imagine Dormer among their ranks is no difficult task.

Natalie Dormer as Margaery Tyrell in Game of Thrones. Photograph: 2016 Home Box Office, Inc. All

This isn’t Dormer’s first foray into video games, having reprised her role as Margaery Tyrell in the video game version of Game of Thrones in 2014, but it’s her first time taking on an entirely new character in a game, and there was enough left to surprise her in the process. Where she was able to develop Tyrell over several years, working almost in tandem with a writing team who knew her strengths, Dormer arrived to the soundbooth to find a fully fledged character to voice. “Hours and hours of work has been put into each character’s psychology, which you weren’t a part of,” she says. “Then it’s up to you to do what you’re told. Not to put too fine a point on it, you give them the last remaining kernel that they need to bring the thing to life … It was a challenge.”

She says this challenge didn’t take away from her enjoyment of the process but that she found the fun in the experience, viewing it as a way to help her grow as an actor, and a storyteller. “You’re trying different things out, seeing what works, seeing what doesn’t work, nailing it on the game, trying lines different ways, and you really do kind of have a giggle – that’s my best way of describing it.”

And while she may not play games herself, Dormer is excited by the continued future of storytelling in video games. “I am increasingly understanding gamers and the gaming world. The addictive quality, the immersive quality, the sophistication of the storytelling … I truly understand it now. We learn and grow.”