Rosamund Pike was determined to embody fearless reporter Marie Colvin in biographical drama A Private War - and to show 'a woman in all her complexities' on screen. Georgia Humphreys hears more about the intense filming process.

In February 2012, Marie Colvin, one of the most celebrated war correspondents of our time, was killed in a rocket attack in Homs, Syria.

Now, a new biographical drama, A Private War, sees London-born actress Rosamund Pike portray the Sunday Times reporter, who was on assignment for the newspaper - alongside photographer Paul Conroy, played in the film by Jamie Dornan, who escaped with a leg injury - when she died.

In the wake of her death, Colvin's sister Cathleen and her three children launched legal action in the US against the Syrian government, filed through the Centre for Justice and Accountability, charging it with arranging her death.

And on the day of our chat with Pike, Judge Amy Berman Jackson, of the US District Court for the District of Columbia, ruled Colvin was deliberately targeted by the Syrian government and ordered it to pay 302 million US dollars (£230 million) in damages.

"It's the most astonishing verdict, such a resounding declaration by the judge in the States that the Assad regime has been found guilty on all counts of targeting the media, silencing journalism, killing Marie," says 40-year-old Pike, known for roles such as Bond film Die Another Day, thriller Gone Girl and 2005's Pride and Prejudice.

"It's colossal, it's everything Paul Conroy, who Jamie [Dornan] plays, and Marie's sister Cat Colvin, have been fighting for, and the Marie Colvin Journalists' Network.

"It's just huge, so we have the answer to that and it's a very, very, very good day."

A Private War, which also stars Tom Hollander and Stanley Tucci, is filmmaker Matthew Heineman's feature debut and, in a world where journalism is under attack, shows how American expat Colvin was an utterly fearless and rebellious spirit, driven to the frontlines of conflicts to give voice to the voiceless.

After years of reporting from places such as Iraq, Afghanistan, Libya and Tamil-held Sri Lanka (where she was struck by shrapnel from an RPG and ultimately lost sight in her left eye), it was travelling to the besieged city of Homs, Syria, where 28,000 innocent civilians were trapped in brutal conditions, which proved to be the most dangerous assignment of her life.

Once Pike heard about the script for the film - through Amma Asante, her director on the biographical drama A United Kingdom - she made it her task to read it.

She also pored over an article by journalist Marie Brenner about Colvin published in Vanity Fair, which A Private War is based on.

"I had a lot of convincing to do," the actress recalls of being cast in the lead role.

"I don't look much like Marie. I'm younger than her, I'm not American. There's a lot going against me. But I really wanted it. She entered my soul somehow when I first read that article. I don't know why.

"I don't have the desire to serve like she did. I don't have the courage. But I do understand about having a vocation that takes you suddenly out of your own daily life and then drops you back in. The distortion, or the dis-junction between the two, can be troubling."

Making the film involved a "long process of gaining people's trust" for Pike.

"Actually, inadvertently, I realised I was put in a position of a journalist," she continues, "because with Matthew Heineman, the director, I embarked on this series of trying to get as many people who knew Marie, and had worked with her, as possible [to talk to us], and at first met a level of resistance, because there's a lot of suspicion around a Hollywood-isation of someone you love; you worry the person will be delivered back to you in a form you don't recognise and there doesn't seem to be any upside."

But breaking down the barriers "so the tales you're being told are not just the safe ones, but you get to the real stuff" was rewarding, Pike adds.

It meant a lot to her when she saw all of Marie's friends and colleagues from the Sunday Times at the London Film Festival screening of A Private War last October.

"I think people don't always realise that as an actor, however sort of lightweight and vain we seem, the main objective is to disappear and focus intensely on someone else," the thoughtful star suggests gently.

"And I think people don't necessarily realise the care that's going to be taken with someone, that you're going to pore over every detail of their mannerisms; the way they walk, the way they hold a pen, the way they hold a cigarette, the way they hold a notebook, the angle of their head, the laugh - all of it, you're going to be trying to embody."

And embody she does. A Private War is a powerful piece of film, in which we truly get a picture of Marie as a complex person - one who was "so strong", notes Pike, but also had inevitable moments of vulnerability.

"It doesn't take away from the strength, it's just that sometimes the very cost of exhibiting that strength and living that strength can be shattering to the nerves at another moment," elaborates the actress, who has two children with mathematical researcher Robie Uniacke.

"Marie has a vibrant romantic life too and often that's taken away from women who are smart and on film too. I knew that if the film's got it right, here is a chance to show a woman in all her complexities.

"It's a private war, isn't it? It's someone who went away from the pack into the most dangerous place on earth, but it's also the cost of when you're at home alone and what you've witnessed and seen."

A Private War is in cinemas now