Ryan Phillippe found it hard to grasp playing a war photographer.

The 'Cruel Intentions' star - who plays war photographer Greg Marinovich in his latest film 'Bang-Bang Club' - says he found it difficult to "understand psychologically" how those who take pictures of conflict manage to stand back and watch the devastation.

He said: "That was sort of a difficult thing for me to understand psychologically. That was definitely the hardest part for me, to understand how you could just let something happen. I can't imagine just being able to stand back but I guess it's just part of the job."

The 36-year-old actor added that being a father to Ava, 11, and seven-year-old Deacon - whom he had with his ex-wife Reese Witherspoon - means he wouldn't be able to stop himself from taking action if he were to see someone in trouble.

He told The Independent: "From a personal aspect that was something I did struggle with because I cannot imagine, as a father and as a sensitive person, not getting involved or taking some sort of action."

The heartthrob added that he was unsure about the photography profession as a whole because of the idea that it "exploits people in peril" and shows things that should remain behind closed doors.

He said: "Not to compare that to being famous and pursued by the paparazzi in any way, but that feeling of being an unwanted presence when something should be private, that's something I really struggled with."