Entertainment Weekly's special "Holiday Movie Preview" issue hits newsstands this week, and peering ominously from its cover is Johnny Depp as Sweeney Todd. Inside the issue is a one-on-one interview with Depp and an in-depth feature looking behind the scenes of the long-awaited film adaptation of the  Stephen Sondheim musical that puts to rest any question of its star's singing abilities. You can hear for yourself when the soundtrack is released on Nonesuch Records December 18. For now, EW says: "Johnny Depp can actually sing."

Some skepticism on the part of Sweeney fans is understandable. Neither Depp nor Burton has made his name in musicals. And according to EW, Burton has never been a fan of those "burst-into-song movie-musical conventions. But he has always loved the heightened, melodramatic mien of Sweeney ... and he's managed to enlist Depp in creating a remarkably faithful film adaptation in which most of the action unfolds in song."

Still, the complexity of a Sondheim score can be a daunting challenge even for the most seasoned of singers, let alone a relative novice. Depp had been in a band in LA in the early '80s, but never sang in it. ''I knew I could stay in key to some degree,'' he tells EW. ''But I didn't know if I could sustain a note, or belt one out.''

Sondheim himself wasn't worried. He OK'd Johnny for the part even before hearing him sing a note as Sweeney. ''I figured he'd have a light baritone,'' Sondheim says in the article. ''You can hear it in his speaking voice. I love him as an actor, and always have. Put those things together, I didn't hesitate for one second.'' Depp, needless to say, was pleasantly surprised by the composer's vote of confidence.

He received the same support from Burton, who, upon hearing the demo Depp had made of the pivotal song "My Friends," was more than pleased. Depp tells the magazine that Burton gave him just "the reaction I was praying for.''

Actress Helena Bonham Carter had a different challenge in taking on the role of Mrs. Lovett. As the wife of the director, she had to overcome talk of nepotism. But this only strengthened her resolve: ''I think I had to be righter than right to prove I was right to play Mrs. Lovett," she says in the article. "But it had been in my blood. I wanted to be her when I was 13, when the show came out. I went around with a Mrs. Lovett hairdo.''

Sondheim again proved to be the perfect actor's ally and came down fully in support of Bonham Carter. ''Even in a recording studio, wearing a schmatte, she is as beautiful and sexy as they come,'' he says in the article. ''She knew what she was doing."

With release of the film and the accompanying soundtrack approaching—both are due out next month—the composer remains confident in his casting choices, Depp chief among them: "There are very few people who can act and sing at the same time,'' Sondheim tells EW. ''He's one.''

To read the complete Entertainment Weekly cover story and the accompanying interview with Johnny Depp, visit ew.com.