Even though he had never sung before, Johnny Depp did not let this get in the way of taking his most challenging film role yet, the one of the serial-killing barber Sweeney Todd in Tim Burton’s remake of the Stephen Sondheim musical.

The movie is directed by Tim Burton, Depp’s long-time collaborator, and co-stars another frequent collaborator of the filmmaker’s, Helena Bonham-Carter, who portrays the murderous Mrs. Lovett. The actress has expressed her amusement on several occasion at the fact that being Burton’s partner, mother of his child and soon-to-be born second child, did not spare her the effort and nervousness of an audition for the part.

Depp himself has said he was very doubtful that he could accomplish the singing requirements of his role. Indeed, interpreting an odd, eccentric, out-of-the-ordinary character, even if a criminal one, is not something new to Depp.

The actor has honed his skill with unique heroes such as an easily goose bump-y Ichabod Crane in “Sleepy Hollow” or an unusual candy-maker with seemingly little appreciation for children in “Charlie and the Chocolate Factory” and of course the wily yet terribly endearing Captain Jack Sparrow in the “Pirates of the Caribbean” trilogy.

During a press conference in London, where “Sweeney Todd: The Demon Barber of Fleet Street” premieres Monday, Depp confessed: “I never sang before in my life, so I had to kind of find my way to it. I didn't know if I would be able to hit a note, to be honest,” Reuters reports.

He asked a friend for help, recorded a song from the musical and then had producer Richard Zanuck’s blessing, when the latter heard the recording.

“I just thought it might be a great opportunity to try to find a new Sweeney, a different Sweeney, in a good way a slightly more contemporary, almost like a punk rock Sweeney,” Depp said of his understanding of the character.

Sweeney Todd is a man who has been wronged beyond bearing by Judge Turpin, portrayed by Alan Rickman. He is sent to jail for a crime which he did not commit and upon release, learns that his wife and daughter have been taken from him. Bereft, driven beyond his power of endurance, he transforms into a blood-thirsty, revenge-seeking murderer, who only feels complete when the razor in his hand.

And Depp probably makes a unique job of imperceptibly making the audience sympathize with this homicidal character and actually feel compassion for him. A hard task the more so as the movie, while predominantly in tones of gray, is dripping in bright red blood from Sweeney’s innumerable victims.

“I've seen productions where they've tried to be a bit more politically correct, and 'Let's lessen the blood', and it really deflated the impact of what the story is,” Burton said during the press launch.

He has said that one of his first definitive ideas of the movie was that there would an abundance of blood.

Sacha Baron Cohen co-stars in the role of Pirelli, a rival barber that threatens to reveal Sweeney’s secret identity.

While the movie is rated R due to scenes of violence and gore, there is already ample talk that it can become contender for Best Picture Academy Award, while Depp, Burton and Bonham-Carter herself have been named as possible nominees themselves. One question keeps surfacing among movie critics that have seen the movie before release (and are forbidden from revealing details): is there too much blood for “Sweeney Todd” to be recognized as the best movie of 2007?