Rosamund Pike says working with real refugees on her new movie 'A Private War' ''changed the energy'' of the project.

The 39-year-old actress plays the lead role in the upcoming drama - based on the life of celebrated war correspondent Marie Colvin - and worked with documentary maker Matthew Heineman, who was able to interview refugees who had been displaced from the conflict zones on which the film is based.

The 'Gone Girl' star revealed that it ''changed the energy so much'' because the film's director was able to draw from the experiences of real people.

In an interview with Collider, she said: ''It changed the energy so much because Matthew coming from a documentary background literally interviewed hundreds of people who were displaced people from the various regions of the conflict regions we were covering - we filmed everything in Jordan.''

Although she learnt a lot from the project, Rosamund endured ''so many confusing emotions'' during filming, and she recalled a scene where she was able to work with women and children from the besieged City of Homs.

She said: ''I walked into it and Matt said, 'OK, 90 per cent of these women are from Homs and this was their truth you can talk to this one maybe this one. And pointed out certain women that were prepared to tell their story and what I got was their truth and so the emotional impact of that was huge. It was a very blurred line between fiction and reality and it was exciting it was moving, I had so many confusing emotions during that that it was quite troubling and that happened, again and again, that's just one example.''