'This event was a seismic turning point for several people'

When you buckle in to watch what promises to be an intense and visceral war film - particularly one that's co-written and directed by 28 Days Later writer and Civil War director Alex Garland-you don't expect the opening scene to be of the 1980s-style aerobics-themed music video for Eric Prydz' 2004 dance anthem Call on Me.

- Will Poulter, Alex Garland, ex US Navy SEAL Ray Mendoza and more tell Rachael Davis about the viscerally intimate Warfare, a story of soldiers in Iraq

The music video, which featured a room full of scantily-clad women (and a man) dancing in a sexually suggestive manner, was a sensation in the mid-2000s - not least among soldiers posted in Iraq during the War.

This, Garland explains, is why the video makes the perfect opening to Warfare, his intimate film which follows a group of US Navy SEALs in the heart of the conflict.

"You can imagine exactly why this group of young guys would love this video, with these very beautiful women sort of dancing around, and the sort of comic element of - in the middle of this hyper-sexualised aerobics class-there's this other young man in there," says the English director, 54.

"But the key thing is that watching that particular video had become a ritual for this particular group of soldiers. They would watch it before going out on operations in a slightly ritualised, possibly slightly superstitious way. And what a perfect way, therefore, given that that was the process before going on an operation, that we start the film like that as well."