Johnny Cash has canceled concert and book promotion tours through December because he is ailing from Parkinson's disease.
"He's been sick for a while, but it's not been to the point where he's needed medication. It's now gotten to that point," said Heidi Robinson, a spokeswoman for American Recordings, Cash's recording company.
The 65-year-old singer canceled his appearances after promoting "Cash: The Autobiography" on Monday's "Good Morning America."
Cash revealed his condition at a Flint, Mich., concert Saturday after he dropped his guitar pick and nearly fell over while trying to pick it up, according to a concert review in the Flint Journal.
After telling the crowd he had Parkinson's, the audience laughed.
"It ain't funny," he said, according to the review. "It's all right. I refuse to give it some ground in my life."