Video clips posted online by fans at Sunday night's performance showed John breaking down in tears as he told the cheering crowd he could not go on any longer. The 72-year-old singer said he had walking pneumonia and was assisted off stage.

Tour promoters Chugg Entertainment said John was resting and doctors are confident he will recover.

"Elton John was disappointed and deeply upset at having to end his Auckland concert early last night," the promoters' statement said. "At this stage, all remaining shows will go ahead as planned."

The concert was part of John's Farewell Yellow Brick Road tour. The tour lists performances at Auckland's Mt Smart Stadium on Tuesday and Thursday.

He thanked the concert attendees via an Instagram post and apologized for ending the show early.

"I want to thank everyone who attended tonight's gig in Auckland. I was diagnosed with walking pneumonia earlier today, but I was determined to give you the best show humanly possible," John wrote. "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."

The New Zealand Herald reported that John told the crowd he was ill but that he didn't want to miss the show. He slumped on a stool and required medical attention after performing "Someone Saved My Life Tonight," but recovered and continued to play, the newspaper reported. Later, as he he attempted to sing "Daniel," he realized he had no voice left and was escorted off stage.

John had just returned to New Zealand after performing at the Academy Awards in Los Angeles. He won an Oscar for best original song for his theme song for the movie "Rocketman."

According to the Mayo Clinic, walking pneumonia is an informal term for a milder form of pneumonia that isn't severe enough to require hospitalization or bed rest. It affects the respiratory tract and is most often caused by bacteria.