An anthem by Somali-born rapper K'Naan has become the signature tune of this year's World Cup after being used in Coca Cola commercials and going to number one in 14 countries.
But Wavin' Flag was not written as a football song - beneath its celebratory tone is the story of its creator's narrow escape from a life of war and his subsequent rise as a hip-hop star and global role model.
K'Naan was luckier than most Somalis when his country fell into civil war in 1991.
He was just 13 when his mother persuaded a US embassy official to let them leave on the last scheduled Somali Airlines flight, and the family moved to New York before settling in Toronto.
"I have pretty good examples of what has happened to those who hadn't made the plane," he says.
"It's not good. Either they become militia boys, fighting all that time 'til now, or they've died."
K'Naan's cousins, who he was close to as a child, are among those who stayed. The rapper says he attracted more trouble than they did when he was growing up.
"So I think a lot about that. If they had to be in that world, imagine what it would be for me. I was the kid that they used to follow into danger zones. I was the one always in the front line of things.
"I would say I'm very lucky to be here."
When Wavin' Flag was originally released last year, it told K'Naan's story, including the optimistic chorus, sung from his younger self's point of view: "When I get older, I will be stronger, they'll call me freedom, just like a waving flag."
The song, originally an album track, is "about facing the odds and coming out of darkness - despair to hope, that kind of transition and transformation", K'Naan says.
After it was selected by Coca Cola to be their theme for the tournament in South Africa, lyrics about "so many wars, settling scores" were replaced by lines about champions taking the field, and others about rejoicing in the beautiful game.
But the message and spirit of the song still shine through, the artist believes.
"The happier version contains some kind of melodic power that still pulls people into feeling something other than just a regular, mundane pop song," he says.
"I think it's a curtain opener, it takes you back to the original, and maybe because of the original you might find other songs."
The memorable chorus is still there and the song is on the A list of both BBC Radio 1 and Radio 2, meaning it has heavy airplay in the UK.
"Before that, what do you hear?" K'Naan asks. "You don't hear songs that have any message at all on popular radio. I think it's still miles more of a message-based song than what it's playing alongside right now."
Much of the rapper's music, he says, reflects the violence and anarchy of his home country. "That experience is what defined me. It made me the person I am today."
While some American rappers glamorise the gangsta life, K'Naan writes with the painful experience of having seen friends shot dead.
"Some of my songs are more violent than a 50 Cent song, but it's just a different perspective of looking at violence," he says. "We look at it from two different lenses."
If life as a teenager in North America was a new start, it was far from easy.
"I fell into the traps of immigrant life and economic disempowerment, living in metro housing projects and dealing with all the trouble that come along with that," he explains.
"My friends there in my teenage years started either going to prison or getting killed. That was the real wake-up, when I had lost quite a few of my friends in North America."
His musical career began to take off at the age of 20 after he delivered a spoken word piece to the United Nations High Commissioner for Refugees criticising the UN's Somali aid missions.
In the audience was Senegalese superstar Youssou N'Dour, who was impressed enough to take K'Naan under his wing.
Despite being a cause for celebration in Africa, the World Cup gives further cause for concern in Somalia, where Islamist militants have put a ban on watching matches because such sports, along with pop music, are deemed un-Islamic.
Two people were killed in a house where people were watching a game last weekend, and militants have warned other football fans that they will be publicly flogged, or worse.
"That's a pretty sore spot for me," says K'Naan, who waved his country's flag at the star-studded pre-tournament concert in Johannesburg.
"I'd heard that some people were executed for watching it. It really hurt me because so many Somalis around the world were tuned in to that thing because of my performance, as well as their love for the game.
"It was such a proud moment because I brought out the Somali flag onto the stage in front of millions of people. That's the thing that so many of them are talking about.
"I just don't want to have been responsible for people being hurt because they wanted to see their Somali singer get on stage or something. That's been a real tough thing for me to even think about. It might not be true at all but it's a thought."