Okay, Natalie Dormer. If you're going to be interviewed by The Irish Times, then you're going to have to do some "local material". It was nearly 10 years ago that the English actor took up the role of Anne Boleyn in The Tudors. Since 2012 she's played the calculating Margaery Tyrell – a woman in charge of her own destiny – in the celebrated Game of Thrones. The former was shot in Ardmore Studios; the latter in various bits of Northern Ireland. Local material?

"Yes. I spent the last five years going back and forwards to Belfast and enjoying beautiful landscapes to shoot Thrones. I met my other half shooting The Tudors 10 years ago. My great- great grandmother is Irish. So I have an emotional connection to the place."

Ah, yes. Dormer has been romantically entangled with busy Irish director Anthony Byrne since 2011. More “local material”, please.

“Soda bread blew my mind. We still get Lyons tea bags shipped back home. And King’s Crisps. I am the one carrying King’s Crisps and Lyons tea when leaving Dublin.”

I saw a woman having about two pound of Kerrygold butter removed from her luggage in Dublin Airport the other week. “You can get that at Waitrose, darling,” she says. “But you can’t get Clonakilty black pudding.”

You’ll do very well, Ms Dormer. You know how to play ball.

The actor turns up this week in an off-kilter horror film called The Forest, as a woman who travels to the Aokigahara Forest in Japan – site of ritual suicides – to find her missing twin. The shoot must have kicked up a deal more cognitive dissonance than a journey to Ardmore Studios.

“Yes. I didn’t know anything about Aokigahara before the script came my way,” she says. “I googled it when the character was googling it. That was my first introduction. I wanted to leave myself with some mystery. She is unprepared and I wanted to be also. I had never been to Japan myself. And the film was shot in order. So, when you see me in the car looking at the lights of Tokyo, that really was my first time seeing that.”

Steady work

Dormer does seem to have her head firmly screwed on. Raised in Reading, she toyed with studying history at Cambridge before lunging for drama school. Now 34, she has enjoyed 10 years of steady work, but there were hiccups at the beginning. In 2005, she bagged a significant role in Lasse Hallström's Casanova. Great things were expected in the aftermath, but the business of show is a cruel business.

“Yes, that was a sort of baptism of fire,” she says. “I was unemployed for nine and a half months. I was temping to buy Christmas presents for my family. That taught me a valuable lesson: never take anything for granted. I actually was glad I had that shock early on. I will never be complacent about the job.”

Given certain historical inconveniences, it shouldn't need to be said that Dormer didn't survive the full run of The Tudors, but she made the role of Anne Boleyn all her own. The show doesn't get enough credit for weaving complex history in with the debauchery. It's a clever piece of work.

"Michael Hirst, who wrote the show, knows his Tudor history," she says. "He wrote Elizabeth with Cate Blanchett. So when he departs from history it is a conscious decision. I tried hard to reflect the woman in her religious attitudes. She was a genuine Protestant, and that evangelical side is very accurate. I canvassed Michael to put that in, rather than cast her as Lady Macbeth."

All-purpose otherness Dormer has a singular, heart- shaped face that sticks in the memory. Of Norwegian descent, she radiates an all-purpose otherness – reinforced by clean, sly delivery – that allows both Anne and Margaery Tyrell to stand out from the furniture.

Dormer is oddly protective of the clever, unflappable Tyrell. The granddaughter of Olenna Tyrell, played by a fearsome Diana Rigg, Margaery worms her way into advantageous marriages while keeping a cautious eye permanently on the looming executioner’s axe.

“I watched the first season as a fan and enjoyed it very much,” she remembers. “I remember Anthony watching those first episodes and saying: ‘You have to watch this. The writing is great.’ When Sean Bean had his head chopped off, I was as surprised as anyone. So I really had to keep my nerves under control when I went into the audition room.”

Her turn in the second series immediately boosted her profile. She was cast as Cressida in The Hunger Games franchise and began an unstoppable rise to fan favour. Her name is now mentioned whenever a superhero sequence receives a reboot.

When we last saw Margaery Tyrell, she was languishing in jail. Somehow one suspects she will not be kept down.

“She’s a sincere human being,” Dormer says. “She genuinely has a good heart. Being politically savvy doesn’t make you a bad person. But I think that when women are portrayed that way, that’s how it often seems. Women have to strive in the public eye. But that doesn’t make them bad people.”

She’s adopting an evangelistic tone now. Testify, sister.

Metaphor for life "There's a spectrum of female characters there. You can be talking about The Forest as a horror movie. You can talk about Game of Thrones as a fantasy. You can talk about The Hunger Games and the dystopian future. All good writing is a metaphor for life."

We can all see ourselves in these kings, warriors and dragon tamers?

“Audiences feel able to explore the human condition through these fantasies,” Dormer says. “That’s very important.”

Well put.