08/21/2012 07:55 EDT | Updated 10/21/2012 05:12 EDT

From the Slums of Kenya to Buckingham Palace

Women sit with their newborn babies in a ward of the Lagos Island Maternity Hospital in Lagos, Nigeria, Monday, Oct. 31, 2011. Amid the millions of births and deaths around the world each day, it is impossible to pinpoint the arrival of the globe's 7 billionth occupant. But the U.N. chose Monday to mark the day with a string of festivities worldwide, and a series of symbolic 7-billionth babies being born. Nigeria is Africa's most populous country with more than 160 million people. (AP Photo/Sunday Alamba)

He has performed for Queen Elizabeth, dined at Buckingham Palace, and rubbed elbows with Sir Elton John, Will.I.Am and Stevie Wonder.

Think we're talking about Bob Geldoff or Bono? Think again. His name is Henry Kangethe, a former street kid from the slums of Nairobi and a member of the Slum Drummers. If you haven't heard of him -- or them -- yet, you may soon.

The 13 members of the Slum Drummers -- nine men and four women -- pulled themselves from lives on the streets of Kenya's most desperate slums to perform with instruments made from trash on stages around the world. Now they're using their music as an instrument of hope, reaching out to street kids in the communities they came from.

We saw the Drummers for the first time last week on the recommendation of a friend who said if we closed our eyes, we'd never imagine we weren't listening to pros.

The slum towns that surround Kenya's capital city are among the largest in the world. We've seen them many times. Hundreds of thousands of the desperately impoverished inhabit districts like Kibera and Kawangware, often without access to clean water, education, or employment.

Kangethe described to us his life growing up in the Kawangware. The oldest of seven children, he often lived on the streets to escape the fights commonplace in his home. When his mother tracked him down and dragged him back, he escaped again.

During one of bleak period on the streets back in 2005, as he tried to eke out a living, he came to a realization, "I wasn't living the life I had always expected."

Chatting with other street kids, Kangethe heard about open auditions for a new music and theatre project. It was targeted at homeless kids.

Standing along 80 other hopefuls, Kangethe tried to repeat simple drum beats. He drew on his experience of dancing and drumming on the streets to pass the time. The experience, along with a natural talent, paid off. He won the part.

The instruments are a key part of what makes the Slum Drummers unique. "Our instruments represent where we come from," says Kangethe.

The drummers make their own instruments from garbage collected in the Nairobi slums. Drums are made from plastic bins and aluminum pots. Spray paint cans become shakers. Even plastic shopping bags are pressed into service, their rhythmic rustling adding an element not unlike a hip hop record scratch.

The drummers even invent entirely new instruments, like the "tubaphone" -- a row of plastic drain pipes that have been carefully cut to produce specific tones. Hit with a mallet, the tubes produce resonant notes you might swear came from an electric synthesizer.

Kangethe and his fellow drummers have performed throughout Kenya and beyond, including Brazil and Italy's Umbria Jazz Festival, one of the largest jazz festivals in the world. Then came the biggest opportunity of their lives.

In 2011, British musician and producer Gary Barlow saw a YouTube performance of the Slum Drummers. Impressed with their style, he travelled to Kenya to meet the drummers. He asked them to perform at the Diamond Jubilee celebrations in London for Queen Elizabeth.

"At first we didn't believe. We thought he was just saying it as a joke," remembers Joel Muiruri, another of the Slum Drummers.

It was no joke. On July 4, they joined a children's choir from Uganda and the UK Military Wives Choir onstage in front of Buckingham Palace, performing a special piece composed by Barlow and Andrew Lloyd Webber.

Backstage, the band was approached by a bevy of international music stars. Will.i.Am offered to open a show in Nairobi and donate the proceeds to support the Drummers. Stevie Wonder hugged the band members and said their music had inspired him. The Queen shook their hands, offered words of encouragement, and showed a keen interest in their homemade instruments.

Back in Kenya after the Diamond Jubilee, the drummers are still star struck and a bit stunned. "Sometimes I feel like it was a dream," says Muiruri.

The Slum Drummers are looking to the future and dreaming of traveling the world. Marco Nardo, project manager from the Italian charity Group for Transcultural Relations which is currently supporting the drummers, says the group is seeking a local manager to mentor and manage the group's career to they can continue to build their identity.

Meanwhile, the group continues to perform around Nairobi's slums, acting as role models for other street kids. Their lyrics urge street youth to stay in school and avoid drugs.

"Our shows are a message to them, a message of hope," explains Kangethe. "Even for them they can change."

This message is reflected in the poetry of one of the Slum Drummers, Michael Njenga Wanjiku, who went blind last year because he couldn't find medical treatment in the slums. In his poem "African Child" he wrote,

"Am an African child and I have dreams, dreams that are so sweet as an ice cream and sometimes I just want to scream at the top of my voice coz am truly a blessing and there is no guessing and without me Africa there's something you are missing."

Craig and Marc Kielburger co-founded Free The Children, and are authors of the new book Living Me to We: The Guide for Socially Conscious Canadians