"There are 26 songs in it. It's like 70 to 75 percent singing and 80 or 90 percent music — more like 90 percent," Tim Burton told The Envelope backstage at Lincoln Center just moments before 17 minutes of "Sweeney Todd" were previewed to an audience for the first time, thus dismissing the rumor that he dumped much of the beloved music of the Broadway classic while adapting it to screen.

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While he kept much of the music, Burton did change, radically, the dramatic presentation of the original musical, deliberately turning it into a horror movie.

"What's interesting is what you can do in a movie that you can't do on stage — get up close to the actors," he said. "I always felt that those old actors like Peter Lorre or Lon Chaney or Boris Karloff have a way about them that's very unique to those styles of movies. This material would really lend itself to that kind of old horror-movie acting style."

Many skeptics of this film adaptation believe Burton could turn this into a truly horrible movie by casting so many non-singers in a musical: Johnny Depp, Alan Rickman, Sacha Baron Cohen and his own fiancé Helena Bonham Carter. Surprisingly, he cast them all before knowing if they could carry the tunes.

"When I asked Johnny to do it and he said, 'Yeah, I think I can do it,' I didn't know if he could sing, but I knew him enough to know that if he didn't think he could do it, he wouldn't do it," Burton said. After Depp accepted the role, he promised to do a recording of his singing voice and send it to Burton to show him. For a long, long time Burton waited for the proof to arrive.

"It took a while," he said. "I didn't hear anything from him for a while. He's very private. I let him go and do his thing and he sent me a thing and I listened and it exceeded my expectations."

Now he believes that Depp is "fantastic" performing the music in the film.

The fact that Depp isn't a polished, bravura crooner doesn't bother him — he likes the realistic quality of all of these actors' singing voices.

"It's very strange," he conceded. "I didn't plan to do this. Practically everybody in the film is not a singer and it's one of the hardest musicals to do. For me, it gives it another layer that I think is really great. It surprised me. I didn't do it on purpose. It just sort of happened that way, but I'm glad it happened that way."

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