The hugely anticipated "Batman Begins" sequel "The Dark Knight" was screened for the first time publicly over the weekend, giving members of the press a first look at Heath Ledger's performance as Batman's arch-nemesis The Joker -- the last role the actor completed before his untimely death in January.

The debut of the film came with mixed emotions for Christopher Nolan, the director and co-writer of the original film and "The Dark Knight."

"It's extraordinarily bittersweet to have Heath not around and see the impression that he's making on people," Nolan said in an @ The Movies interview Sunday. "At the same time, I have to admit to feeling great relief and so forth that people seem to be receiving the performance very much in the way the Heath would have liked and would have intended."

Nolan said the positive reception of the Ledger's performance is important in that it confirms that he didn't let the late actor down.

"It means that I think I did my job OK in terms of putting together his performance and letting it speak the way he intended -- which is big responsibility for any film director under any circumstances, let alone when the actor's died," Nolan said.

Starring Christian Bale as Bruce Wayne and his crime-fighting alter-ego Batman, "The Dark Knight" follows The Joker's rise to prominence in Gotham City and the debilitating effects his maniacal ways have on the Caped Crusader and those around him.

Ledger died Jan. 22 at the age of 28, while the "The Dark Knight" was in post-production phases. Despite the unfortunate circumstances, Nolan said that he stayed true to what Ledger had delivered to him as The Joker and didn't let the actor's death alter the plans he originally had complete the film.

"I think and honestly believe that the performance in the film is exactly the way it would have been if Heath had not passed," Nolan said. "The truth is, the character he created was so incredibly different to who he was, that it made it easier to be more objective about it. This monstrous creation that he'd given us for the film was so opposite to who he was and what it was like to work with him."

And Nolan considers himself lucky to have had the opportunity to get to know him as that actor and person.

"I think it's a great testament to his skill as an actor how different those two things were with him," Nolan said. "Anybody that knew him, knew that he was warm and gentle and lovely he was to have around, and anyone who sees The Joker he created, I think, will be blown away by the ferocity and extremity of the performance. It's an incredible piece of work."

"The Dark Knight," also starring Michael Caine, Gary Oldman, Aaron Eckhart, Maggie Gyllenhaal and Morgan Freeman, opens in theaters July 18.