United Kingdom, July 21 -- Billy Joel insists he is "okay".

The Piano Man crooner, 76, worried fans in May when it was announced he had been diagnosed with normal pressure hydrocephalus (NPH), a rare but treatable condition that affects the brain and can impair hearing, vision and balance.

In an update about his condition he has now urged fans not to worry about him, telling People: "I know a lot of people are worried about me and my health, but I'm okay.

"What I have is something very few people know about, including me, no matter how much you try to research it. I'm doing my best to work with it and to recover from it."

Billy's diagnosis was first shared publicly in a statement through his team, and he added balance issues were his ...