Elton John has revealed at a gala performance of his new musical The Devil Wears Prada, for which he wrote the lyrics, that he is physically unable to see the show due to ongoing vision problems.

On stage, the 77-year-old singer thanked his husband David Furnish, “who has been my rock.”

“I wasn’t able to attend many of the previews because, as you know, I lost my eyesight. That’s why it’s hard for me to see it. But I love hearing it and man it sounded good tonight,” he added.

In September, John revealed that a serious eye infection he contracted in France in July had left him blind in his right eye and “limited vision” in his left.

“I am recovering, but it is an extremely slow process and it will take some time before the affected eye can see again,” he wrote in a statement shared on social media. “I am so grateful for the excellent medical and nursing team and my family who have taken such good care of me over the last few weeks.”

Last week, John told Good Morning America that his eyesight was delaying the release of his next album with his longtime partner Bernie Taupin.

“Unfortunately I lost my vision in my right eye in July because I had an infection in the south of France and I haven’t been able to see for four months now and my left eye isn’t so good anymore,” he said. “So there’s hope and encouragement that it’s going to be good, but… I’m kind of stuck at the moment because I can do something like that (the interview), but going into the studio and recording, I don’t. I don’t know because I can’t see any text at first.”

The Devil Wears Prada has just opened in London’s West End at the Dominion Theatre. Sunday evening’s gala performance was held to raise funds for the Elton John Aids Foundation.

The Devil Wears Prada, originally a novel by author Lauren Weisberger that was later adapted into a film, tells the story of Andy, an aspiring journalist who becomes assistant to the notoriously difficult fashion magazine editor Miranda Priestly. In the musical, Priestly is played by US model and actress Vanessa Williams.

The star-studded event was attended by many famous faces from the fashion world, including Vogue editor-in-chief Anna Wintour, who has long been rumored to have inspired Priestly’s character.

Speaking to the BBC on the red carpet, Wintour said: “It’s up to the audience and the people I work with to decide whether there are any similarities between me and Miranda Priestly.”