Mo Farah has said growing up in poverty gave him the boost he needed to become a champion distance runner.
The athlete, who will compete for Great Britain in this summer's Olympics in Rio de Janeiro, grew up in Somalia, sharing a basic shack with seven other people.
But asked by the Radio Times if he would have been a double Olympic champion if he had not lived in such conditions, he said: "No. I think that gave me a massive boost.
"It made me realise in life, you have to work for it."
Mo, who recently revisited the house for a BBC One documentary, said of his childhood: "As long as you had food in your mouth and you were breathing, that was fine. That was a good life. There was nothing more. No opportunities.
"As a kid, we didn't have toys - we played in sewage, we played with what was there. The house I grew up in was tiny - eight of us, all crammed into one room.
"If you see where I live now, it's a big difference, and I'm grateful because I can show people that if you work hard at something, you can achieve."
At the age of eight, the runner came to live in London with his parents and was separated from his twin brother, Hassan, as he was too ill to travel. They were not reunited for a decade.
Mo said: "With the civil war, everybody moved about and we didn't know where he was. It was only when mum went back that she found him."
But the 33-year-old said he might not be where is now if he had grown up with his twin.
He said: "Everything happens for a reason. There's no point chasing the past.
"But I don't know if I would have achieved as much if Hassan had been here, because we always encouraged each other to mess about.
"He was the cheeky one and he'd say something and I'd stand up for him and get into a fight! It might have been a distraction."
This week's Radio Times is on sale on Tuesday July 26.