Ozzy Osbourne has cancelled his North American tour in order to have further treatment for Parkinson's disease.
The rock veteran, 71, revealed his diagnosis a month ago, and will travel to see doctors in Switzerland in April.
He had been due back on stage in Atlanta, Georgia, at the end of May.
"Unfortunately, I won't be able to get to Switzerland for treatment until April and the treatment takes six-eight weeks," he said. His UK tour, which stars in October, is still on.
Discussing his health in January, he said he has a "mild form" of Parkinson's, which he found out about after suffering a fall a year ago.
He then had surgery on his neck, which he said "screwed all my nerves".
A statement on his website said the tour had been cancelled to allow him "to continue to recover from various health issues he has faced over the past year".
He had previously postponed the US tour last April after his fall.
The former Black Sabbath frontman said he was "so thankful that everyone has been patient".
He continued: "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."
In January, wife Sharon said they had exhausted options for treatment in the US.
"We've kind of reached a point here in this country where we can't go any further because we've got all the answers we can get here," she said.
"So in April, we're going to a professional in Switzerland. And he deals with... getting your immune system at its peak."
Osbourne's next scheduled show is the first date of his UK tour, in Newcastle on 23 October. His new album, Ordinary Man, is set for release on Friday.