The 40-year-old stars in the political drama, which he also directs and he said that making his hair look like the late Monkees singer Davy Jones and Bee Gees musician Barry Gibb was tough, reported Contactmusic.
"I hated it, Alan Arkin got away with keeping his current hairdo. But I had to grow out this kind of Davy Jones, sort of Barry Gibb thing that I had on my head. I knew I was going to be doing the movie fair enough in advance that I could grow it out.
"Everybody really went for it, there was no vanity with the actors - Rory Cochrane with his moustache and his wig, and everybody else with the moustache and the glasses, there was no, 'No, I gotta look good in the movie.' It was all, 'How much can I look like the real people', he said.
