Discussing the casting of Naomi Watts and Penn as former CIA spy Valerie Plame and her husband Joe Wilson at the Cannes Films Festival, the director admitted that he was delighted to get his first choice actors for the political drama.
"What's incredible about this movie is that my first two choices to be in the movie were Naomi Watts and Sean Penn. Normally you have your first choices only to end up with your third choices and they're great. We actually got our first choices," he said.
"Sean Penn is probably the greatest living actor. I went into the film thinking that and he did not disappoint. It's very hard when you have expectations that high. Life must be tough because everyone expects him all the time to be extraordinary, but in reality he just continually is extraordinary."
Liman explained that Penn's gradual transformation into Wilson was akin to "watching a horror movie".
"He would hang out with Joe Wilson and each day he would become more and more like Joe Wilson," Liman commented. "It was like watching a horror movie, Invasion Of The Body Snatchers or something. The personality of Joe is being sucked out and going into Sean! It was one of the most magnificent things I've ever seen."
> Complete Coverage: Cannes 2010