Ozzy Osbourne has cancelled the North American leg of his world tour to undergo medical treatment in Switzerland.
The 71-year-old heavy metal star revealed in January that he has been diagnosed with Parkinson's disease and was also recovering from injuries he sustained after a fall at home.
Osbourne, who is known to fans as the Prince of Darkness, was due to kick off the US leg of his No More Tours 2 tour in May, but will now travel to Europe to undergo specialist medical treatment.
In a statement, Osbourne said: "I'm so thankful that everyone has been patient because I've had a shit year. Unfortunately, I won't be able to get to Switzerland for treatment until April and the treatment takes six to eight weeks.
"I don't want to start a tour and then cancel shows at the last minute, as it's just not fair to the fans.
"I'd rather they get a refund now and when I do the North American tour down the road, everyone who bought a ticket for these shows will be the first ones in line to purchase tickets at that time."
Earlier this year, Osbourne and his wife Sharon said when they learned of his Parkinson's diagnosis they planned to go abroad for treatment. Osbourne also admitted that he found it difficult to keep the facts about his health a secret.
He said: "To hide something inside for a while, it's hard. You never feel proper, you feel guilty.
'm no good with secrets. I cannot walk around with it any more because it's like I'm running out of excuses, you know?"
Osbourne's new album, Ordinary Man, is set for release on Friday.