Sienna Miller on the sniper’s widow she portrays: 'I feel like she’s my sister'

Sienna Miller says she feels like a sister to the widow of a US Navy SEAL who she plays in her new film.

She takes the role of Taya Kyle, the wife of the most accurate sniper in the force’s history, in Clint Eastwood’s American Sniper.

Chris Kyle, played by Bradley Cooper, served four tours in Iraq and received 10 medals for heroism only to be murdered at a Texas gun range last year.

Miller told the Standard in New York: “When I met Taya, from the first moment we spoke on the phone, it was like we’d known each other for ever. I feel like she’s my sister. We became very close.”

Explaining how Kyle helped her prepare for the role, she said: “Taya was so open and gave Bradley and I access to every single email that she and Chris had sent to each other when he was away, which is really personal and incredibly intimate …

“[It was] incredibly intimate email correspondence over a long period of time with good, bad and everything in it — an entire relationship.”

Miller, 32, found it hard to detach herself on set. “Normally you can sit in the corner and stick some Sigur Rós on and zone out for the sad bits but not [in American Sniper],” she said.

“You have to go through a couple of weeks of sadness and feeling uneasy like everything’s wrong and have to shake it off and move on.”

Of Eastwood as a director, she said: “He taught me an awful lot. My process can be really thorough and I can … over-complicate it. Clint would say, ‘Just say it’. That’s an amazing acting lesson.” Along with a role in Foxcatcher, American Sniper marks Miller’s film comeback following the birth of her daughter Marlowe in 2012. She was praised by her co-star Cooper, who said: “I was always a massive fan of hers … She’s the top. There’s no BS and she throws herself into it completely.”

He said the film was not political, explaining: “It’s not a movie about the Iraq war. It’s a movie about what a soldier like Chris has to go through — the dilemma and the horror of it, the battle internally and with the family. It’s not a political movie at all.”

American Sniper is released on January 16.