"I couldn’t sing," Ronstadt said, "and I couldn’t figure out why. I knew it was mechanical. I knew it had to do with the muscles, but I thought it might have also had something to do with the tick disease that I had. And it didn’t occur to me to go to a neurologist."
"Parkinson’s is very hard to diagnose," she said, "so when I finally went to a neurologist and he said, ‘Oh, you have Parkinson’s disease,’ I was completely shocked. I wouldn’t have suspected that in a million, billion years."
The legendary singer, most famous for "You're No Good," has released 30 studio albums and 15 compilations. The folk-rock artist has collaborated with the likes of Frank Zappa, Johnny Cash, Dolly Parton and Neil Young, to name a few.
“No one can sing with Parkinson’s disease,” Ronstadt said. “No matter how hard you try.”
Ronstadt, 67, said she believes she may have had Parkinson's "for seven or eight years already, because of the symptoms that I’ve had."
Winner of 11 Grammy Awards, two Academy of Country Music Awards and an Emmy Award, and nominated for numerous others, Ronstadt has now officially retired from singing.
Ronstadt’s memoir, "Simple Dreams," due out September 17, does not discuss her diagnosis or the loss of her singing voice.
2014: The Year in Music [PHOTOS]