LONDON — British singer Elton John, 77, told a theater audience on Sunday that he had lost his sight.

One of the biggest-selling artists of all time, the “Tiny Dancer” and “Rocket Man” star attended the launch of a show in London’s West End but said he had been unable to watch the performance.

“As some of you may know, I have had issues and now I have lost my sight. I haven’t been able to see the performance, but I have enjoyed it,” John said, according to the Daily Mail.

John…