John has spoken about the dynamics of his relationship with George in his recent autobiography "Me: Elton John", reports mirror.co.uk.
Michael tragically passed away on Christmas Day in 2016 and John tagged him as "one of the most brilliant songwriters this country has ever produced."
Despite this, there was a time in George's life when he didn't see eye-to-eye with Elton and even ordered him to "f*** off" as tempers began to fray.
Speaking about the passing of Micheal on his Apple Beats 1 Radio show, three months after the death, John said: "Not only was he a good friend, but he was probably one of the most brilliant songwriters this country's ever produced, and certainly one of the best vocalists ever.
"One of the best in the world."
What came between the two music though was Micheal's reported drug use and John said he didn't take kindly to him trying to persuade the "Careless Whisper" singer to go to rehab to address the problem.
Talking about what happened in his autobiography, John said that the situation ended in an expletive-filled argument.
He said: "George Michael really didn't want to know. I nagged at him because I was worried and because mutual friends kept contacting me, asking if I could do something.
He wrote an open letter to Heat magazine, most of which was concerned with telling me, at considerable length, to f*** off and mind my own business."
John felt that he was speaking from experience as he had spent time in rehab during 1990, where he kicked his drug addiction.
Micheal was reportedly more annoyed after John had told the magazine that Micheal was "in a strange place."
Elton was then had openly critical of Micheal's album titled "Patience", which he had described as "disappointing".
This led to Micheal to let rip at John in an open letter, which read: "Elton John knows very little about George Michael and that's a fact. Contrary to the public's impression, we have spoken rarely in the last ten years and what would probably surprise most people is that we have never discussed my private life. Ever."
Micheal levelled at John that his only knowledge of his life was from rumours on the "gay grapevine".
John wrote in his autobiography about his regret at the situation that happened: "I wish we hadn't fallen out. But more than that, I wished he was still alive. I loved George. He was ludicrously talented and he went through a lot but he was the sweetest, kindest, most generous man. I miss him so much."
John has since spoken frankly about Micheal on US TV show "The Talk".
He said: "He couldn't get it, George. And he resented the fact that I had hinted that maybe he change his life a little bit and he'd be happier if he tried something else. The person has actually got to want it."
( With inputs from IANS )