Watch Alicia's documentary here

At just 27 Alicia Keys is one of America’s most successful musical exports: she has sold 25m albums worldwide, won 11 Grammys and performed with everyone from Stevie Wonder to David Bowie. On tour she is dressed by Georgio Armani. Bob Dylan is a fan. More than once she has topped the lists of the “most beautiful woman in the world”.

Her life was not always so privileged: she grew up in Hell’s Kitchen, a tough neighbourhood of New York, and understands all about the fear that drives young people to carry weapons with sometimes fatal consequences: 20 teenagers have been stabbed to death on the streets of London already this year.

Once that level of violence hits the streets, everyone feels the need to protect themselves, she says. Even she, aged 14, used to carry a knife. “Gang culture was everywhere and there were altercations all the time. You’d often find yourself in situations where you wished you had something more than just your hands. So I would carry around a little shank \,” she says.

“When my mother found it she was so upset and couldn’t understand why I had it. It was simple, I told her. It was like that on the street — I needed a knife, just in case.” Her mother was horrified and wanted to move, “but there was nowhere to go. At that time you couldn’t get away from it — knives were everywhere. I definitely understand that feeling of wanting to protect yourself”.

Keys was in London last week on the UK leg of her European tour and to host the Black Ball to raise money for her Aids charity Keep a Child Alive. She thinks Boris Johnson, London’s new mayor, could learn a lot from the strategies employed by Rudy Giuliani when he was New York mayor and drove down the dizzying crime rates through his policy of zero tolerance. “New York is a different place these days. Of course there is still crime there, but you can go out and feel safe,” she says.

In her case it was Terri Augello, her single parent mother, who saved her from her seemingly inevitable future. Augello had to leave her daughter while she went out to work. “She had to be terrified: I was a girl in Hell’s Kitchen and she knew I wasn’t staying inside\,so one of the best things she did for me was to keep me busy,” says Keys.

Knowing her daughter was desperate to play the piano, Augello made it her priority to set aside money for music and dance lessons. “It was the best thing she ever did for me,” says Keys. “I’d go and hang out with my friends, but would only do it for 45 minutes as I had to get to my next class. My extracurricular lessons gave me a real sense of focus and drive and they helped to keep me out of trouble.”

Keys says she is constantly reminded of the way her life could have turned out when she comes across old friends from Hell’s Kitchen. “One of my friends got into a car with somebody who had something on them they shouldn’t have and now they’re in jail. That could have been me!” she shrieks.

Keys believes music lessons could play a part in helping disadvantaged children: “Who doesn’t love music? It gives you discipline and something to be proud of. It breaks my heart that there are kids out there who would love to play an instrument but can’t because their parents don’t have the money or don’t think it’s important.”

She also thinks it is imperative to present positive opportunities to the young and disadvantaged: “It’s not surprising that kids get into a rut when they never see anything to aspire to. It is so important to have a dream. So many young people want to go to college, but no one even helps them with how to fill out the application forms. So it’s no wonder they end up slipping into crime and don’t make anything of themselves.”

Alicia in Africa, a film about Keys’s charity, is on Channel 4 at 4pm today

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