Johnny Depp has called Tim Burton crazy for casting him in new movie musical SWEENEY TODD, because the heartthrob star can't sing. Depp is currently filming his role as the 'Demon Barber of Fleet Street' in a movie version of Stephen Sondheim's Broadway musical, due for release next January (08). But the actor confesses he has a terrible singing voice. He says, "Tim took a risk when he asked me to play Sweeney Todd because neither he nor I knew if I could sing when I accepted it. "I went into the recording studio with a friend of mine to see if I could do it. My singing's not unlike the mating call of a rutting stag. It's a strange sound, but I haven't been fired yet."