Sienna Miller was humbled by the opportunity she felt she received when awarded the role of Taya Kyle in the Oscar-nominated film American Sniper. She admits it’s hard to say no when Clint Eastwood asks you to play a role in a film he is directing.

“I would have been happy to make the tea on Clint’s set much less be a part of the actual film,” Miller said during a recent interview with WGAL. “He’s phenomenal. As a young girl dreaming of being an actress, he’s one of the people I dreamed of working with. I still can’t believe this has all happened.”

American Sniper opened in theaters nationwide this weekend. It is based on the best-selling novel of the same name by Chris Kyle (played in the film by Bradley Cooper), and tells the true story of the Navy SEAL who is credited with being the most prolific sniper in American military history. The film received six Oscar nods this past Thursday, including Best Picture, Best Actor for Bradley Cooper and Best Adapted Screenplay.

Sienna Miller–in her role as Taya Kyle–plays a wife who stands by her husband’s side throughout four incredibly dangerous tours of duty, She found herself overwhelmingly challenged by the emotional and psychological effects the war had on him when he returned home to her and their two children.

“Ultimately, the title is American Sniper, and it is a story about Chris Kyle, but I think his and Taya’s relationship is a huge part of the book and the film,” Sienna Miller said. “I do think by looking at the relationship, it grounds the war. It helps you find the human behind the Navy SEAL. It shows what the man faced while trying to raise a family and be a husband, but it also shows the immense sense of duty he felt to serve his country when he wasn’t in active service. He felt that there were people dying that probably wouldn’t be dying if he had been there. I think that dynamic is really interesting, because his relationship with his family was a huge part of his life and was well-represented in the film.”

Sienna Miller worked closely with Taya Kyle–Chris Kyle’s now-widow–during production of the film.

“Taya is so unbelievably open, and so wanted this film to be a good representation of his and Chris’ relationship. She was just the easiest woman to talk to and so generous,” Miller said. “She kept all of their email correspondence while he was on his tours, and let Bradley and I have access to them. There were hundreds of really interesting emails, and she let us go through them so we could get a sense of what their relationship was like.”

“Of course, there were questions you have to ask and you have to be really forensic in your examination of someone if you want to do them justice, but at the same time, she never made me feel uncomfortable at all,” Sienna Miller continued. “She said, ‘Just ask me anything. I want to help. I want you to get this right. Please don’t be shy or worry about me getting upset.’ She told me almost everything, and we became really close as a result of that. So, while by nature I feel uncomfortable to ask those sorts of questions, I felt I had to serve the film and serve the performance and do my work.”

Sienna Miller talks about her role in "American Sniper" with @MarkAShanahan http://t.co/lzgBQeoiJl

— The Boston Globe (@BostonGlobe) January 11, 2015

Chris Kyle, as most people now know, died in 2013–shot down at a gun range in Texas. At the time of his death, the former Seal was being sued by Jesse Ventura, the former Minnesota governor and ex-professional wrestler, over claims in the book that Kyle punched him in a 2006 bar fight over unpatriotic remarks. That suit was transferred to Taya Kyle after Chris died.

“I have such a new-found respect not only for the men and women in the military and who are serving in combat, but the spouses left behind,” Sienna Miller said. “I think in a way they’re making as much of a sacrifice because it’s impossible to raise a family and not know every day whether your husband is going to live or die. It has to be an unbelievable situation to find yourself in. Of course, Taya Kyle understood who her husband was, but at the same time, it’s an enormous sacrifice on both sides. Before I started the film, I hadn’t given enough thought to that.”

Sienna Miller’s commentary alone makes it abundantly clear that American Sniper is a must-see, and likely destined for Academy Award fame. Will you be checking out Bradley Cooper and Sienna Miller in this powerful film?