The 66-year-old canceled his tour in early July, after performing 10 shows in what he described as "agony."
"I was a ticking time bomb," John told The Sun in July. "I guess I could have died at any time. I feel so lucky and grateful to be alive."
In a message posted on his website, John said he was "deeply touched" by get-well cards and messages from fans.
"Your well wishes have touched me deeply and will play a big part in my recovery," he said.
"I cannot wait to see you all and thank you in person when I resume my concert schedule later this year. In the meantime, please know that I consider myself a very blessed man to have such caring and considerate fans."