Emotional Sir Elton John struggled to hide his grief as he watched footage of Princess Diana's funeral on a TV special - but claimed she had been "airy fairy" with her true friends.

The superstar singer had to ask the cameras to stop filming while footage of him performing 'Candle In The Wind' at the ceremony was played.

A show promising Sir Elton "talking more candidly than ever before" also saw him open up about his battle with drugs and bulimia and confusion over his sexuality.

Grief: Elton John with Princess Diana at a Memorial Service for designer Gianni Versace in 1997. He says the Princess became 'airy fairy' with her true friends towards the end

Sir Elton told VH1 RocDoc 'Me, Myself and I': "I think in the end with Diana she trusted the wrong people.

"She didn't trust the people she should have trusted, her true friends.

"I always thought the people that really felt for her and really were true to her she just was a bit airy fairy towards in the end."

Sir Elton, who told how he found out about Diana's death through a fax sent by a friend offering condolences the next morning, became emotional while watching footage of the funeral.

Emotional: John performs Candle In The Wind at the Princess's funeral, he says it was one of the most surreal things he's ever

He said: "Me playing at the funeral of Princess Diana was one of the most surreal things I have ever done.

"You didn't show any emotion. It's not the sort of thing you do at something like this.

"What was going through my mind was, 'Don't f*** this up. Don't sing a wrong note. Don't sing the wrong note. Be stoic. Don't break down and just do it to the best you can possibly do it without showing any emotion whatsoever.' "My heart was beating quite a lot, I have to say.

"This is an unreal experience and I hope I never have to do it again."

Then Sir Elton turned slowly to the camera and asked: "Can you stop? Thanks." The moving scene ended with the screen fading to black.

The singer was reunited with lost friends John Lennon and Princess Diana thanks to technical wizardry in a TV look-back at his career

In the show screened in the US on Thursday night, Sir Elton admitted his struggle with drug addiction in the late 80s almost killed him before he cleaned up his act.

He said: "Charlie, toot, whatever you want to call it.

"It gave me more confidence initially to join in, to be part of the gang.

"I was quite a shy person. I found it made me more verbose and I relaxed and could join in.

"But like anything I have ever done as far as alcohol or drugs, I did it too much.

"I'm not one of these people who could do a line and just do a line.

"I would have to do the gram of coke and then send out for more.

"It was a horrible drug for my addictive personality.

"Because I took so much of it I needed to drink more or to smoke more spliffs to come down from it.

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Reunited: TV magic saw Sir Elton step into Yoko Ono's place in old friend John Lennon's Imagine video

"The more I stayed up the more didn't eat.

"Then the more I went to bed and the more I ate, then I threw it up.

"It became a vicious circle of drugs, alcohol, marijuana, bulimia." Sir Elton said he broke his own rule never to perform under the influence of drugs or booze.

But he claimed becoming chairman of his beloved Watford Football Club in the 80s saved him.

He said: "With Watford it gave me discipline at a time when I desperately needed discipline.

"Otherwise I would have gone completely off the rails if I hadn't had the football club.

"I had nothing other than my career.

"It saved my life." His ultimate turning point came in 1990, when he checked into a Chicago hospital for six weeks.

He said: "I knew that this was the time I would either have to make the decision I was going to get sober or I was going to die, and I didn't want to die."

Sir Elton told how he had his first gay sexual experience in a San Francisco hotel aged 23 - and admitted his guilt and regret over his ill-fated marriage to Renate Blauel.

He said: "I had never had sex. It was the first time I really had sex, let alone with a man." Sir Elton said of Renate: "She is the classiest woman I have ever met and I do love her desperately, but it wasn't to be.

"I was living a lie." He told of his regret over the heartache he caused her, saying: "I'm not exactly proud of that, to say the least."