He may have started out singing cover versions on cheap compilation albums, but Elton John went on to become the fifth highest-selling recording artist of all time.

He was the first musician to enter the US album charts at number one. He has won a Brit award for outstanding achievement three times. And he owns six gold, 38 platinum and one diamond albums.

None of this, however, impressed his father.

Stanley Dwight, a flight lieutenant in the Royal Air Force, never attended one of Elton's shows, and never expressed pride in his son's success. Their relationship was strained until his death from heart disease in 1991.

Writing in his new autobiography, Me, Elton admits he spent his whole career "trying to show my father what I'm made of".

"It's crazy, but I just wanted his approval," the star tells the BBC, in the only print interview about his book. "I'm still trying to prove to him that what I do is fine - and he's been dead for almost 30 years."

Strikingly, however, the star harbours no resentment, describing his father as a "product of his time" - uptight, emotionally stunted and trapped in an unhappy marriage.

"Although he didn't really come to the shows or write me a letter to say, 'well done', I don't think he knew how to," he explains.

 Elton and his father failed to see eye-to-eye

Born Reginald Dwight and raised in Pinner, near Wembley in north-west London, Elton was frequently on the receiving end of his parents' frustration. He spent his formative years in "a state of high alert" amid arguments and "clobberings" from his mum.

"My parents were oil and water. They should never have gotten married," he says. "As you get older, you can see much clearer what they went through, what they tried to do for me at the expense of their happiness."

'All hell broke loose'

His salvation came in rock and roll.

Both his parents were musically inclined - Stanley was a trumpet player with the Bob Miller band, while his mother, Sheila, would bring home new records every week on pay day. One day, she arrived home clutching Elvis Presley's Heartbreak Hotel, a disc that turned Reggie's world upside down.

"I grew up in the 1950s, which was a very conservative age - people peeking behind the curtains, being very judgmental," he says.

"I knew nothing about sex, it was never even mentioned to me. If a girl got pregnant she was sent away and nobody talked about it. It was a very different place.

"Then Elvis Presley arrived on the scene and revolutionised things musically and socially, and then the 60s happened and all hell broke loose".

Initially, the teenager watched these developments as an outsider - in love with the music, but forbidden to participate.

"I was very shy," he says. "I grew up not being able to wear what I wanted to. Winkle picker shoes? No, they were too disgusting. The mods wore chisel toe shoes and anoraks. I couldn't wear those either.

"So when I changed my name and became Elton John, I just went off like an Exocet missile, and I had a great time. I lived my teenage years in my 20s, basically."

 The star compensated for being stuck behind a piano by creating ever-more elaborate stage costumes

The story has been told a thousand times: The miraculous meeting with lyricist Bernie Taupin, a blue-touch-paper appearance at LA's Troubador club, and an unbeatable run of hit albums.

Between 1970 and 1975, there were 11 in all, an astonishingly productive purple patch that generated classic singles like Saturday Night's Alright For Fighting, Tiny Dancer and Rocket Man - the latter of which unexpectedly turned Elton into a sex symbol.

"It was a surprising time," he laughs. "I mean, I wasn't David Bowie, I wasn't Marc Bolan, I was sitting at the piano. But I suddenly became, you know, the object of screaming girls. I don't know why."

Emboldened by success, Elton's outfits became ever more outrageous: Satin capes and winged boots gave way to mohawk wigs, bejewelled top hats and peacock suits adorned with feathers and sequins - the sort of thing Liberace would have worn if he'd had the courage to be really flamboyant.

 Elton's 1970 shows at the Troubador club made his name. "He's going to be one of rock's biggest and most important stars," said the LA Times.

His imperial phase culminated with two sold-out shows at LA's Dodger Stadium in October 1975. With a combined audience of 100,000 fans they were, at the time, the largest concerts ever staged by a single artist.

"He was like Elvis at the height of his career," said photographer Terry O'Neill, who shot the gigs. "It is impossible to try to explain to people today what it was like."

But Elton knew as he played those shows that he would never reach that peak again.

"I was smart enough to know it couldn't last. It's impossible. You just have to accept that there's going to be someone bigger than you."

It's a sense of perspective other artists lack, he says.

"When Michael Jackson said, 'I want to sell more records than Thriller', I thought, 'Oh boy, you're in for a big fall'. Because Thriller was a classic record. It sold 40 million albums, which was huge. You can't have a record coming in at number one all the time."

Sure enough, Elton would have to wait until 1990 before he returned to the top of the charts. The wilderness years, while hardly hit-free, saw him split temporarily with Bernie Taupin and record an ill-advised disco album, Victim Of Love.

Behind the scenes, his drug and alcohol intake was spiralling out of control. In his memoir, he describes having seizures and witnessing his voice go "haywire" as his "unbelievable appetite" for cocaine grew stronger.

The drug had initially given him a "jolt of confidence and euphoria," but as addiction took hold, he became erratic and violent. In 1983, after filming the video for I'm Still Standing, he woke up with his hands throbbing, unaware that the night before, he'd stripped naked, punched his manager John Reid and methodically demolished his hotel room.

Although the recent biopic Rocketman depicts I'm Still Standing as Elton's hymn to sobriety, it actually took him another seven years to kick the habit.

The turning point came when his then-boyfriend Hugh Williams checked into rehab, plunging Elton into a fortnight-long cocaine and whisky binge. Eventually, he dragged himself to the clinic, where Williams confronted him on his behaviour.

"You're a drug addict, you're an alcoholic, you're a food addict and a bulimic," he said. "You're a sex addict. You're co-dependent".

"Yes," said Elton, "yes, I am," and started to cry.

So on 29 July, 1990, he entered rehab in Chicago to treat "three addictions at once".

In his book, Elton reprints a poignant break-up letter he wrote to "the white lady" during his treatment. "I don't want you and I to share the same grave," it reads.

He kept his word: The singer has now been clean for 29 years, during which time he's revitalised his career, married film producer David Furnish, written the hit soundtrack to the Lion King, launched the stage version of Billy Elliot and become father to two children, Zachary and Elijah.

He says the autobiography was written for them: A document they could read after he's gone that would tell the unvarnished truth.

"I want them to know that their dad was being honest, and he made something of his life after a few hiccups along the way", he says.

 Elton with his husband David Furnish and their sons Zachary and Elijah

It was Elton's sons that prompted him to give up touring, too.

"My kids were only going to grow up once," he writes in the memoir. "Music was the most wonderful thing, but it still didn't sound as good as Zachary chatting about what had happened at football practice."

With typical grandiosity, Elton's farewell tour is scheduled to run for three years, with the final show set for 17 December, 2020, at London's O2 Arena.

But that is definitively not the end. Last week, Bernie Taupin posted a photo of himself at the writing desk, composing lyrics. Can Elton confirm they're intended for him?

"Yes, they are," he says. "I said to Bernie, 'I'm going around the world for three years, why don't I write?

"You know, I wrote the whole of the Captain Fantastic album on the SS France, sailing from Southampton to New York, and I didn't have a tape recorder. So I remembered everything I wrote in my head: The chord changes, the sequences, everything.

"And I said, 'I'd like to go back and do that, instead of going into the studio and writing on the spot'. It may not be successful but I just want to try it."

What's more, he's already cooking up plans to play concerts after the farewell tour.

His "dream thing" is to put on a theatrical residency, in the style of Kate Bush's Before the Dawn extravaganza in 2014.

Like her, Elton would delve deep into his back catalogue, prioritising lesser-played cuts like Amoreena, Come Down In Time and Original Sin over fan favourites like Your Song or Rocket Man.

"I've sung these songs nearly 5,000 times, some of them, and although they're wonderful songs, and I'm very appreciative of them, I've sung them enough," he says.

"If I do perform again, I would like to do songs that I think are just as good as the ones that have been popular for 50 years, but haven't had the chance to emerge."