A voice artist to loop Heath Ledger in 'The Dark Knight'?

Just in from Hollywood Elsewhere:

How will Warner Bros. and the Dark Knight team handle Heath Ledger’s unrecorded looping sessions? Slate’s Kim Masters is reporting that “it would be unusual for director Chris Nolan to have all the sound that he wants at this early stage [for a film coming out in July], and that on a big-budget franchise picture like The Dark Knight, a producer opines, “looping would be the norm.”

The obvious solution would be to use a voice artist “and there are rumors that the studio will do that,” Masters writes. “If so, the studio’s denials would be understandable: Warner wouldn’t want the public to be listening for variations in the voice when the movie is released. But the producer assures: ‘With a good voice artist, you would never know the difference.’”