Ozzy's got voice problems...

Ozzy Osbourne has been forced to postpone at least one date on the US OZZFEST tour, in order to rest his vocal chords.

The 56-year-old rocker is under strict doctor’s orders to avoid all activities of a screaming nature, having already received treatment for throat problems.

The concert’s promoters decided late on Thursday night to reschedule the Somerset, Wisconsin leg of the festival from this Sunday (August 7) to September 10.

Black Sabbath had previously been forced to cancel their performances in New Jersey, Indiana and Ohio since the tour began on July 15, due to Ozzy’s illness.

Explaining his decision to the Minneapolis Star-Tribune, promoter Randy Levy said:”You gotta do Ozzfest with Ozzy,” but admitted that several of the other acts might not be able to make the rescheduled date.