Concerns are growing over Ozzy Osbourne's health after a last minute concert cancellation in Germany. Is he OK? 

Rumors of Ozzy Osbourne's failing health started to fly following a last minute concert cancellation in Germany this week.

Ozzy's people went into damage control mode immediately telling TMZ that the cancellation was due to "vocal concerns" and not because of health problems. There was no warning for fans who had gathered for the show. When Ozzy was supposed to take the stage, a man came out and announced that Ozzy was not going to perform. His official website does still list another European date in Begium tonight.

Ozzy's son Jack Osbourne just revealed this week that he has been diagnosed with Multiple Sclerosis. Both Jack and Sharon Osbourne have spoken about Jack's diagnosis, but Ozzy has remained mum.