NEW YORK — At first, the scene on the screen seems like one common in many of Tim Burton and Johnny Depp's famous collaborations. The production design is atmospheric and evocative. The actor sports a thick English accent. He seems tortured and haunted by the information that has just been delivered to him.

And then, after a few lines are exchanged between Depp and his co-star Helena Bonham Carter, something utterly shocking (even for a Tim Burton flick) happens: Johnny Depp sings. This is "Sweeney Todd: The Demon Barber of Fleet Street," perhaps the biggest gamble of the holiday movie season.

There are five weeks until "Sweeney Todd" opens December 21, and Burton is still working on his latest ambitious endeavor, a full-fledged live-action musical (his first) based on Stephen Sondheim's Broadway hit. "We're not quite done with it. It's weird to be doing this kind of thing," he told MTV News in an exclusive interview Wednesday night, moments before showing three scenes, totaling 17 minutes of the film, to an enthusiastic audience at Lincoln Center.

Clad in an all-black outfit (you were expecting something else?), highlighted by some spiffy black-and-white-striped socks, the revered director of "Batman" and "Edward Scissorhands" described a film long in the making. Burton admitted he was never much of a musical-theater fan, but to the surprise of no one, the bloody tale of Benjamin Barker — locked away for 15 years for a crime he didn't commit — was an exception even early on. "I saw it when I was a student. The mixture of humor and horror and emotion felt like it was perfect for me."

At the event, Burton showed scenes he described as "Sweeney comes home," "Sweeney gets pissed" and "Sweeney gets down to business." The images that followed were not especially surprising for a Burton film (Depp storming down the streets of London, bellowing that he wants vengeance). If the background music were ignored, you'd be forgiven for thinking you were seeing a deleted scene from "Sleepy Hollow."

It is the music that carries this film, though. Early on, Burton made the somewhat controversial choice to cast nearly all non-professional singers. That includes Depp, Burton's wife and frequent collaborator Carter, Alan Rickman and Borat himself, Sacha Baron Cohen.

But clearly all eyes will be on Depp when "Sweeney Todd" is released. The film is undeniably his, and the clips don't lie: The performance looks to be a tour de force. Save for a shock of white in his hair, it's Depp's voice that will draw the most attention. Each of the three scenes showcased the actor front and center, and Burton admitted that his version of the story focuses on the man much more so than Carter's Mrs. Lovett, who played a larger part in the Broadway production.

For Depp, Sweeney may pose the biggest challenge yet in a remarkable career predicated on taking chances. Believe it or not, there was a time when portraying a pirate in the key of Keith Richards was considered insanity, at least by some nervous executives at Disney. It's one thing to do an ironic take on a pirate; it's another to star in a Tony Award-winning musical having never sung onscreen before. His part in the 1990 John Waters musical "Cry-Baby" was dubbed over, and though Depp played guitar in rock bands before he ever tried acting, he's never worked the mic. Burton laughed as he remembered that the actor had nearly done a song in "The Corpse Bride" before jumping into this challenge.

As for the biggest question of the day — can Depp sing? — the answer, at least judging by these scenes, is a resounding yes. Much in the way that Ewan McGregor and Nicole Kidman made the music of "Moulin Rouge" work thanks to decent natural talent coupled with emotion behind the words, Depp sells his character from the start.

Burton's interest in directing "Sweeney Todd" began about 10 years ago, he said. When he started reconsidering the project, he found something that sparked some casting ideas. "I did a drawing a while back, and it kind of looked like [Johnny] and Helena before I even knew [them]. I thought, 'That's strange. That means something,' " he recalled.

When "Sweeney Todd" trailers hit the Internet and television, audiences began to wonder how full-fledged a musical this would be. Let the question be put to rest: As is clear from the footage shown and Burton's comments, "Sweeney Todd" is a musical, featuring nearly wall-to-wall music.

"Most musicals have 10 pages of dialogue and then they burst into song. The music is threaded throughout this," Burton said. "That's what I liked about it. It's like a silent movie with music. It's like an old horror movie."

Indeed, the final clip made clear that this film will not shrink from horror. In it, Sweeney begins by serenading his blades and then quickly moves to slicing customer after customer. Blood gloriously and unapologetically spurts out, even falling on the camera lens at one point. When asked if he considers his film (which the director said will receive an R-rating) bloody, Burton laughed and said, "Yeah, but it's fake blood," adding, "I would have watched this on television when I was 10 years old."

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