Elton John is to undergo surgery in the coming weeks for appendicitis, and says he feels "so lucky and grateful to be alive".
The singer told The Sun he had been in "agony" during his recent European tour and thought he was suffering from food poisoning.
He said: "I was a ticking time bomb. I guess I could have died at any time."
After performing 10 concerts in pain, he was forced to walk off stage at a show in Germany last Friday, with doctors advising him to cancel all his tour dates.
A statement issued on the singer's behalf said that he had been diagnosed with "appendix abscess surrounding retrocaecal appendicitis".
Once the toxins around his appendix have reduced, the 66-year-old will have surgery but will not return to touring until he is fully recovered.
His spokesman said: "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."