Heath Ledger wanted Christian Bale to actually hit him while filming 'The Dark Knight'.
Ledger starred as The Joker in Christopher Nolan's 'Batman' movie alongside Bale as The Caped Crusader and in one particular scene, Ledger spurred on Bale to physically assault him.
The scene follows an interrogation between Batman and his arch nemesis at Gotham City Police Department and Bale, 43, revealed it was the first scene he shot with the late actor - who was already very much in character as the psychopathic villain.
In the new book '100 Things Batman Fans Should Know & Do Before They Die' by Joseph McCabe, Bale said: "Our first scene was in an interrogation room together, and I saw that he's a helluva actor who's completely committed to it and totally gets the tone that Chris Nolan is trying to create with this. We're not going for actors revealing their enjoyment of playing a wacky caricature. We're treating this as serious drama. You go into character and you stay in the character. I love that. I find that so ridiculous that I love it, and I take that very seriously. Heath was definitely embracing that. When he was in the makeup and the garb he was in character the whole time; and when he took it off he was absolutely fantastic company to be around.
"As you see in the movie, Batman starts beating the Joker and realises that this is no your ordinary foe.
"Because the more I beat him the more he enjoys it. The more I'm giving him satisfaction. Heath was behaving in a very similar fashion. He was kinda egging me on. I was saying, 'You know what, I really don't need to actually hit you. It's going to look just as good if I don't.'
"And he's going, 'Go on. Go on. Go on...' He was slamming himself around, and there were tiled walls inside of that set which were cracked and dented from him hurling himself into them. His commitment was total."
Ledger tragically passed away from an accidental overdose of prescription drugs in January 2008 when he was only 28 and received a posthumous Best Supporting Actor Academy Award
for his portrayal of the DC Comics character.