American singer Linda Ronstadt has announced that she suffers from Parkinson's disease and that it has robbed her ability to sing.

The 67-year-old  - who was the most successful US female singer during the 1970s - told AARP Magazine that she was diagnosed eight months ago and "can't sing a note."

Ronstadt says she began to show symptoms as long as eight years ago, but attributed her inability to sing then to a tick disease. When her hands began to tremble, Ronstadt said she thought the shaking was the result of a shoulder operation.

She said she was "completely shocked" when she finally saw a neurologist and was diagnosed with Parkinson's disease. "I wouldn't have suspected that in a million, billion years.

"No one can sing with Parkinson's disease," Ronstadt said. "No matter how hard you try."

Ronstadt sold tens of millions of records starting in the 1970s with pop hits such as You're No Good and When Will I Be Loved. She was also known for her romances with California Governor Jerry Brown and filmmaker George Lucas.

Here's Linda Ronstadt's version of Smokey Robinson's Tracks of My Tears: