Billy Joel says he’s been diagnosed with a brain disorder … and as a result, he’s canceling all of his scheduled concerts.

The singer announced Friday he is suffering from Normal Pressure Hydrocephalus … which is a brain disorder where excess fluid accumulates in the brain’s fluid-filled cavities.

Billy says his condition has been exacerbated by his recent concert performances … and he’s having trouble hearing, seeing and balancing.

There’s no timetable for Billy to get back onstage and he says, “I’m sincerely sorry to disappoint our audience, and thank you for understanding.”

Billy’s camp says his shows through July 3, 2026, are canceled and tickets will be refunded.

A source close to Billy tells TMZ … he is following his doctor’s recommendations. His doctor has advised him that returning to work is not advisable at this time — but he is doing OK and is improving.

We’re told Billy is on a boat with his wife today in Florida … and he’s already undergone surgery.