He’s the YouTube sensation who turns 17 next month, making him the youngest singer to top the American Billboard Charts since Stevie Wonder in 1963. He has already earned nearly ￡100 million, and analysts claim he’s the most influential person on the internet, ahead of Barack Obama. But unless you’re an eight-year-old girl (or living in close proximity to one), you’re likely to be a bit vague on the whole Justin Bieber phenomenon.

　　Just who is this Canadian cutie pie with the spray-on mop top and the cartoon grin? Did he deserve the Brit award (for best international breakthrough artist) we gave him earlier this week? And what’s the secret of his appeal to the hordes of hopelessly devoted “Beliebers” who’ll be screaming and swooning their way through his new 3D movie, Never Say Never, when it opens in British cinemas tomorrow, and packing concert venues when he tours here next month?

　　Like most child stars, Bieber inherited his ambition. His mother’s dreams of an acting career were derailed when she became pregnant with him at 18. Although she kept in contact with his father, Pattie Mallette raised her boy alone, working in a series of low-paid office jobs in Stratford, Ontario.

　　Little Bieber discovered a passion for music early. In the movie, fans will coo over home video of him, aged about five, staring out from beneath a floppy blond fringe and announcing, “Mummy, this is how I drum!”, before banging out a tight, enthusiastic rhythm on a cheap kitchen chair. He taught himself to play the piano, guitar, drums and trumpet, came second in a talent contest at 12 and began uploading videos of himself to YouTube. That summer, he set down his guitar case in front of a theatre and made almost $3,000 busking covers of songs by his R&B heroes, Usher and Ne-Yo. In a rather adorable, role-reversing moment, he used the money to take his mum on holiday to Disneyland.

　　Meanwhile, those homemade YouTube videos had been spotted by aspiring music executive Scooter Braun. Mallette, a devout Christian, was hesitant because Braun is Jewish. “God, I gave him to you,” she is reported to have said. “You could send me a Christian man, a Christian label!” But after praying with church elders, she decided to hand Braun the reins of her son’s career. And Braun had a strategy ready to roll. “I wanted to build him up more on YouTube first,” he has said. “We supplied more content. I said: 'Justin, sing like there’s no one in the room. But let’s not use expensive cameras.’ We’ll give it to kids, let them do the work, so they feel like it’s theirs.”