It is impossible to write about the complexities of Batman and "The Dark Knight" without mentioning Heath Ledger's powerhouse performance as The Joker. The impact it has on the film is paramount, to say the least. Take it from his co-star's heartfelt declarations of praise, the Oscar talk is serious and spot on.

CHRISTIAN BALE (Bruce Wayne) on HEATH

"It's wonderful that people are recognizing [the possible Oscar nomination]. I love the fact that - regardless of whether it ever comes to fruition or not - the fact that Chris has created in this movie even the possibility that people are talking about accolades for an actor in a superhero action genre movie. Usually that is never even considered. So kudos to Chris for doing that and to Heath for coming forward with that devastating performance. He has raised the bar, completely, with it. He was absolutely committed. I enjoyed working with him immensely. Clearly it is tragic that we are talking about this as his last complete performance. I would love it if he were to be walking in the room right now - he would be talking, he's great company. I looked forward to working with him many times in the future; I looked forward to being his friend for many years to come. But this movie can be a celebration of his talent, and thank you for saying that because he truly deserves that. He was a fierce talent and I was very fortunate to get to witness that talent and work with it and know the man during his lifetime."

GARY OLDMAN (Lieutenant Gordon) on HEATH

"Actors go along - really good actors, as Heath was, go along and they have good careers. It's like they're sort of traveling at subsonic speed, and occasionally they go through the sound barrier. You can think of people like Jack Nicholson in “One Flew Over the Cuckoo's Nest,” Al Pacino in “Dog Day Afternoon”…There's certain landmark performances where you just think that they just fly. And Heath has done that here. He's just tuning in to a radio station - he's got a frequency that none of us can hear. It was like he found something. And I knew it was special the first day I worked with him. I called a friend, and they said 'How is it?' and I said 'It's good, it's good,' and they said 'How's Heath as The Joker' and I said 'He's going to be sensational. You can tell already.' How good he turned out to be is beyond my expectation, really. People talk about the intensity of someone like Christian. And I've heard someone say 'Christian's a method actor.' Well, Christian's still alive. [pause] I mean, Heath, in between takes, would laugh and joke and sit down on the curb and have a cigarette and talk about Matilda. And I think it's just the sort of thing that everybody wants to go 'Oh, it's the role. It drove him…' You'd have to be neurologically fucking mental, you'd have to have a disorder to play a part and let it affect you so much that you can't sleep and that you - you know what I mean? Don't you think? People want a darker story than there really is, because my experience of him, and I don't know if he had substance abuse in the past, and people talk about partying and the stuff he used to do, but I was never witness to that. I worked with a sweet kid who had such a heart, who was a lovely guy. I worked with this guy who was completely committed to the role and the work, wanted more than anything to be taken seriously as an actor. He was on time, he knew the lines, and he was a nice kid.”

Dish: Do you think Ledger will be nominated for an Oscar?

Oldman: Yeah, I think so. I think the Academy tends to overlook movies like this. They somehow seem to not take it so seriously because it just doesn't fall into their thing. They don't tend to look at work in movies like this. But in this case I think the acting is so good, I think his performance is so good, I think it's going to be very hard to avoid it.

AARON ECKHART (Harvey Dent/Two Face) on HEATH

"I had a great time working with Heath. Unfortunately I didn't get to know Heath a lot better than I did, and I didn't work with him as much as I wanted to. But Heath is one of those actors that other actors admire and want to be. To be so young and to be so good and to be so smart is rare. And he loved this character of The Joker. It was his baby. He cared about The Joker very much, making the decisions and really thinking about him and creating him and creating his look. Really putting his stamp on it. It was fun because I was in the trailer while Heath was doing his makeup I would do my makeup, so we got to have that time together and for him to play around with his makeup and me and do the funny faces and the noises and kind of do whatever that brought to us. When we were doing our scene in the hospital, he was amazing.

Dish: What did that do to your performance, when he's clearly doing something wonderful?

Eckhart: You have to step it up. I'm not sure either one of us knew what we were going to do in that scene in the hospital. Heath really drives that scene, so he probably knew better than me. I was going to go off of him. And he started going and I just held on, and then my creative juices started going, and Heath was very accommodating to me and I to him, so we worked really well together and, I thought, came up with something good. Heath is that actor that makes you proud to be an actor. After that scene, I was proud to be an actor, and I said, ‘This is why I love to act.’

Gary Oldman mentioned Chris Nolan just letting Heath go in certain scenes...

Eckhart: I don't think Chris could've stopped Heath if he wanted to. So that's the good news, that Heath felt that he could - Look, as an actor, giving such a brave performance you have to - as a director you HAVE to let your actor go, because Heath needed Chris' trust and felt like Chris would let him do whatever so that he would open up and do things, and let his unconscious come up and his creativity and his imagination and give the great performance that he does. If Chris had tried to shut him down Heath wouldn't have been able to give that performance. And that's why Chris is the great director that he is: he's able to balance the actors with the technical aspects of filmmaking and make this huge entertaining movie as well as a profound psychological thriller.

"I have to say that Heath is foremost on my mind when I think about this movie…which is a good thing. I think that Heath will give me strength as an actor, opening up and being vulnerable and going for the fences and stretching myself as an actor, by virtue of his performance. I think that my time with Heath, however small, will always live with me and make me be a braver actor."

CHRISTOPHER NOLAN

Dish: Can you talk about Heath Ledger's performance and how he found his way into that? This is a performance for the ages, watching him discover how to do this, and then the reality of how you ultimately edited and put the film together using that and what happened to him?

Nolan: Well, to address the second part first. I'm very confident that the performance has been edited exactly as it would've been had Heath not died. It was very important to me that his performance be put out there exactly the way that we had intended it and that he had intended it to be seen as well. Watching him come up with the characterization was a pretty exciting and pretty amazing thing because you're looking at an actor craft an iconic presence for a character, but making it human at the same time. That's an incredible thing to do and the way in which he's done it is extraordinarily complicated and everything about what he does from every gesture, every little facial tick, everything he's doing with his voice – it all speaks to the heart of this character. It all speaks to this idea of a character who's devoted to a concept of pure anarchy and chaos. It's hard to get a handle on how those elements combine. The physicality reminds me of the great silent comedians. It has a bit of [Buster] Keaton and [Charlie] Chaplin about it. The voice is very difficult to imitate. Every film set, one every crew there are dozens of talented mimics who are always taking off different performances or lines that they've heard from actors before, but no one could do The Joker. No one has been able to imitate it successfully. It's very elusive and complicated, but working with Heath you would see that he very precisely worked out every aspect of him.

Dish: Did he talk to you about that process at all, the voice and the movements?

Nolan: Yeah, to a degree. When I was working on the script and he'd gone off to think about what he was going to do with the character he would call me from time to time and talk about the things that he was working on, but the truth is that when you're outside that process before you get to set it's all a bit abstract. So he was talking to me about how he'd been studying the way that ventriloquist dummies talk and things like that, I'd be sitting on the other end of the film going, 'Well, that's a bit peculiar.' But what I'm really hearing is an actor really invested in trying to come up with something very unique. Then when I saw it all come together, the conversations we'd had kind of made sense. I could see where he was coming from with that with the pitch of the voice. He would talk about having it change pitch dramatically in very sudden ways and things like that. That helps the unpredictability of the character. When we were mixing the sound for the film, we let his voice – normally you're sort of flattening out voices to make them clearer, evening out the volume at which they speak, but with The Joker we felt that you had to let it be a little bit out of control in the way that he performed it.

Dish: Were you disturbed at all about all the speculation that Heath went too far with The Joker character ultimately leading to his death? It sounded a bit like nonsense, but nevertheless was out there in the media machine.

Nolan: I'll answer that simply to say that it diminishes his skill as an actor. The job of an actor is someone who takes on a character and distinguishes between real life and a character. Anyone who's spent time on a movie set knows that it's a very artificial environment and the great skill of someone like Heath Ledger or Christian Bale, all these guys is that they can be jobbing along in a workaday environment, and then when the camera rolls, they can find this great character.

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