Mental illness is sure not picky when it comes to choosing its victims. Even the King of Pop, Michael Jackson, had no way out.

In an excerpt from his recently released autobiography entitled "Me," Sir Elton John revealed some surprising details about Michael Jackson.

The Rocket Man described Jackson as the most adorable kid when he first saw him with Elizabeth Taylor. However, through time, John saw how MJ drifted away from the world 'just like Elvis Presley did'.

Elton detailed one of the disturbing instances he had with Michael Jackson. When he invited Jackson in one of his dinner parties, Elton John later found him with his 11-year-old son, quietly playing video games. It was also witnessed by John's housekeeper, making him realize that MJ could not stay along with adults at all.

That was when the speculations about the side effects of prescription drugs affecting the "Thriller" hitmaker.

"God knows what was going on in his head, and God knows what prescription drugs he was being pumped full of, but every time I saw him in his later years I came away thinking the poor guy had totally lost his marbles," John writes in his autobiography.

The singer-songwriter also added that he was saddened to see Jackson be surrounded by people who kept on telling him things he wanted to hear and not the things he needed to hear.

John saw Jackson as "a disturbing person to be around," and he felt heartbroken because of that. Jackson stayed that way until he suffered from cardiac arrest and died on June 25, 2009 -- which was later concluded to be a homicide.

Sir Elton John, Moving On From Drug Addiction

John has always been quiet about his sufferings due to substance abuse, just like the King of Pop. However, instead of ruining him, he saw drugs as something that opened him up and turned him into the man he is now.

In an interview with TODAY, he told the story of how he got curious about drugs and eventually tried it in pursuit of making himself free. From a very shy man, using the substance made him talk more. That was when he liked it more -- but not until his close friend Ryan White died because of AIDS in 1990.

For a decade, stopping was not one of his choices, but the incident that happened to White made him halt from using drugs. Just six months after quitting in the year 1992, he established the Elton John AIDS Foundation as a tribute to his friend.

The foundation, which aims to help people who are living with the disease, is still a non-profit organization up to this date.

Elton John also stated that he is grateful for the years he had sex and drugs, but he now loathes it whenever he looks back at those times.

Together with his husband, David Furnish, he still moves forward after 16 years of suffering and 29 years of making himself feel better.