Out British singer Elton John on Sunday announced that he has been diagnosed with walking pneumonia.

The 72-year-old John made the announcement after a performance in Auckland, New Zealand.

In a social media post, John told his fans that he was “deeply upset and sorry” for his performance.

“I want to thank everyone who attended the #EltonFarewellTour gig in Auckland tonight,” he wrote. “I was diagnosed with walking pneumonia earlier today, but I was determined to give you the best show humanly possible.”

“I played and sang my heart out, until my voice could sing no more. I'm disappointed, deeply upset and sorry. I gave it all I had. Thank you so much for your extraordinary support and all the love you showed me during tonight's performance. I am eternally grateful,” he added.

John is currently on his final world tour, titled the “Farewell Yellow Brick Road” tour. It has 300 dates.

(Related: Elton John wins Oscar for Rocketman song.)