Christian Bale on Interrogation Scene and Heath Ledger "The Dark Knight" (2008)

"Many times I'll work with actors and I can tell they're thinking: 'What are you doing? Why are you going that far with it?' or 'You're nuts!' With [Heath Ledger], I could feel him going: 'I love it!'" 

Watch the video below in which Christian Bale discusses (at the 1:45 mark) the preparation involved behind the now famous good cop- bad cop scene in The Dark Knight. In this scene, Bale's Batman interrogates Heath Ledger's Joker and it's a wonderful demonstration of who these characters are.