Christopher Nolan on Heath in the July 11th edition of Entertainment Weekly:
"The guy had serious nuts. What I needed was someone who wouldn't be afraid of the comparison with Jack Nicholson. And then I saw Heath's incredible performance in
Brokeback Mountain. Such a lack of vanity. This was an actor who wasn't afraid to bury himself in his character - to a massive extent."
I find it so interesting that Nolan looked at that performance and thought to himself, "Now that's the man I need to play the Joker in my next Batman movie." That would probably have been the last role that would have popped into my head after seeing Heath play Ennis. Yet, it shows just how fine an eye for acting - and a gift for understanding actors - Nolan must have to be able to make such a leap. It's almost as impressive to me as Ang's being able to look at much of Heath's earlier work and think that the actor would fit so well in the Ennis role. I guess that's why they're making movies and I'm not.