Johnny Depp is reportedly to have a voice test before composer Stephen Sondheim will allow the actor to star in musical "Sweeney Todd" reports Ananova.

The composer fears his vocals may be too rock 'n' roll to play the murderous barber and serial killer whose weapon of choice is a straight razor, with which he cuts his victim's throats. His friend and accomplice bakes the carcasses into meat pies.

A spokesman for Sondheim says: "He wants to make sure that all versions of his works are the best possible." Tim Burton, will direct the movie, due out in 2008.