Michael Jackson's death - as well as his life - remains shrouded in mystery more than 10 years on.

The King of Pop has been the subject of intense speculation since he died of a drug overdose blamed on his doctor, Conrad Murray, back in 2009.

And scrutiny over his life stepped up last year with the airing of a bombshell documentary named Leaving Neverland, which detailed the claims of two alleged victims who said Jackson had sexually molested and groomed them as boys, using his power and fame to bedazzle their families.

Motown legend Diana Ross was one of the few celebrities to pledge her support to Jackson's reputation in the wake of the documentary, taking to social media to urge fans not to denigrate his memory.

(Image: Getty Images)

"This is what’s on my heart this morning. I believe and trust that Michael Jackson was and is a magnificent incredible force to me and to many others," she tweeted. "Stop in the name of love."

Over their 40-year friendship, much was made of the bond between Diana and her protegee Michael, after she personally gave herself over to the coaching of the Jackson 5 group in their early years.

Their relationship seemed to border on flirtatious much of the time, and their occasional joint performances would see them dance together suggestively, although nothing sexual was ever confirmed between them.

Now a curious fan theory posits that Diana could have been Michael's secret biological mother, rather than Katherine Jackson, who was married to Michael's late father Joseph Jackson.

A user on Reddit has gathered information to indicate Diana had a teenage fling with Smokey Robinson that resulted in Michael's secret birth.

u/jameslieb1 says Diana grew up on the same street as Smokey and has publicly admitted to being in love with the singer. She also moved high schools around the time she could have been pregnant, which may have been to conceal the fact she was expecting.

Diana and Smokey have never publicly spoken about the theory or the suggestion they may have been Jackson's real parents.

Diana was named in Michael's will as a stand-in guardian of his three children - daughter Paris Jackson and sons Michael Jr and Prince, better known as Blanket - if Katherine was somehow unable to take care of them herself.

The pair are believed to have met when Michael was nine, and she took him under her wing as a close friend and confidant - despite their 14-year age gap. In 1978, when he was 18, he described her as a "very dear, close friend that I can tell my deepest, darkest secrets to because I know she won't tell anyone else".

(Image: Zuma Press / eyevine)

(Image: PA)

But fans are convinced there was more to their relationship than just friendship, after rounding up hints both Jackson and Ross appeared to drop throughout their lives.

On The Merv Griffin Show in 1970, Diana seemed to suggest he was her son when she was quizzed on her role in introducing the Jackson 5 to the Motown scene.

"You've added a fantastic group to the musical scene, as the talents go," Merv pointed out.

"Well if you're speaking about the Jackson 5, I don't feel like I've added them, I just opened the door for them and instead of them walking in, they ran in and trampled me as they were coming through the door," Diana laughed.

(Image: Landov / Retna Pictures)

Springing a surprise on the host, she went on: "I love them dearly, we have one of them in the audience, we have Michael Jackson somewhere out there. Where is he? There he is - that's my child! That's Michael! He's being incognito."

The shy youngster stood up and waved to the crowd as Diana looked at him adoringly.

"You know, they've made me work hard because I want to be something - I am - Michael has always been like a son or brother to me, they've admired me, so I try very hard to keep up such an image for them," she told Merv.

"And when I do a show like this they usually sneak Michael in, I really didn't know he was going to be here, I heard about it and I was hoping he would be here. It makes me a little bit stronger because I'm doing it basically for him."

When the Jackson 5 first moved to LA to launch their showbiz careers, Berry Gordy, head of the Motown label, decided Michael needed more stability rather than schlepping from hotel to hotel with his older brothers.

He turned to Diana and asked if she would have Michael to stay with her for a month - and The Supremes frontwoman leapt at the chance.

(Image: Ronald Grant Archive)

She had already primed Michael to tell any suspicious journalists he was eight - not 10 going on 11 - and to spread the word that "the great Miss Diana Ross" had discovered him and his siblings.

Their time together would serve as the basis for the rest of their decades-long friendship - but Michael admitted it also led to other feelings.

"When I was little I used to stay with Diana Ross, me and my brothers we'd stay with her for years," he later told Oprah. "I never said, but I always had a crush on her."

Their intimate relationship turned into public affection in 1981 when they appeared on a TV show together and Diana told him: "I knew you were going to be a giant star, I really did. But I didn't you you were gonna get so sexy."

Michael blushed as he shot back: "You're embarrassing me. Well I always knew you would."

"What?" Diana asked coquettishly.

"Be sexy. Don't you guys think she's sexy?" he asked the crowd as they whooped with approval.

But as the years went by, the pair seemed confused about their bond.

"I'm crazy about Michael and I love him a lot. He's been my inspiration. He's very gentle, wonderful human being, one of the special ones in this universe, and I don't even know if he knows how special he is," Diana gushed.

"So whenever I can be around him, I like it. You like to rub shoulders with talent. He's got good vibrations. His aura is only about love. So I like being with him. I have a feeling that he is going to be, if he isn't already, a tremendous [record] producer."

At the 1981 Oscars, Diana and Michael turned up on the red carpet hand in hand, where they joked about being family.

Asked if they were planning to make a movie together, Diana responded: "We're going to do something soon, he's going to play my son."

(Image: Getty)

Michael laughed as they walked away into the theatre.

In the late 1990s, Diana made yet another suggestion that she and Michael were blood relatives.

"He could be part of my family. We have a lot of the same bone structure and the skin colour's the same," she told one TV interviewer.

"Well Michael does now, because he's had it all done!" joked the host, referring to Jackson's increasing reliance on plastic surgery to tweak his supposed flaws.

Getting angry, Diana shot back: "I refuse you to insult Michael, he's a friend of mine, I love him, and I don't like anyone making fun of him. I get real serious when I talk about Michael... and I think we should really look at his life with compassion, he makes incredibly good - I want to use the bad word - good music."

Diana went on to have daughter Rhonda Silberstein in 1971. The girl's father was Berry Gordy, but Diana told Rhonda her dad was Robert Silberstein - the husband she married when she was two months pregnant.

She also had daughters Tracee Joy and Chudney Lane Silberstein with Robert before their divorce in 1977.

Diana is also mother to Ross Arne and Evan Olav with her second husband Arne Naess Jr, who fell to his death in 2004 in a climbing accident.