CHICAGO (WGN) — Legendary entertainer Billy Joel announced Friday that he is canceling all of his scheduled concerts after being diagnosed with a brain disorder.

The announcement came in a post shared on the Piano Man singer’s Instagram page on Friday morning.

According to the announcement, Joel has been diagnosed with Normal Pressure Hydrocephalus (NPH), a condition that causes an excessive buildup of cerebrospinal fluid (CSF) in the brain’s ventricles.

“I’m sincerely sorry to disappoint our audience, and thank you for understanding,” Joel said.

Joel said in the post that the condition has been exacerbated by recent concert performances, which have led to problems with his hearing, vision and balance.

According to the post, those who have purchased tickets for upcoming concerts will receive refunds.