Sir Elton John's appendicitis - which forced him to cancel a gig in Hyde Park this week - was a "ticking time bomb" which could have killed him, he has said.
The popular singer announced his illness yesterday, having struggled through 10 concerts in "agony" on his European tour before calling doctors.
He told The Sun: "I was a ticking time bomb. I guess I could have died at any time."
"I feel so lucky and grateful to be alive."
The pain forced Sir Elton to walk off stage during a concert in Germany on Friday. A spokesman said the diagnosis had been made "following a number of exploratory scans and blood tests with his medical team in the UK, who advised him to cancel all the dates on his current tour.
The 66-year-old pulled out of the planned London date - where Elvis Costello and Kinks frontman Ray Davies will play - as well as shows in Italy and Germany.
According to his website, he is on a course of "intensive antibiotics" and is expected to undergo surgery "in the coming weeks".
The singer's spokesman said Sir Elton will not return to touring until fully recovered from the surgery and the damage caused by the abscess.
He went on: "Elton is incredibly disappointed to postpone these tour dates. To know that he made such super-human efforts and continued to perform to thousands through his illness only confirms his dedication to his European fans.
"He is eager to be back on top form and return to play the remaining shows starting in early September 2013."
This isn't the star's first health scare. Last year he cancelled a number of shows as a result of a respiratory infection which struck him during a series of US dates. He also missed concerts due to a bout of food poisoning.
In 1999 he had a pacemaker fitted after doctors discovered an irregular heartbeat.
Sir Elton has recently been promoting his forthcoming album The Diving Board, which is due to be released in September.
Organisers of the British Summer Time Festival announced Friday's show will be a free event following Sir Elton's withdrawal and ticket holders will be refunded.
Rob Hallett, the president of international live touring for show promoter AEG Live, said: "We certainly wish Elton a speedy recovery and know that he would have hated for us to cancel the whole day's events because of this.
"In the beautiful surroundings of Hyde Park and the incredible weather we are having, our show goes on. And there's no better way to enjoy the start of our final weekend than with a free event for all to enjoy, with some excellent headline artists topping off even more great entertainment in our 10-day event."