Golden boy Michael Phelps might have become a world sports icon on the back of his incredible haul of eight gold medals from the Beijing Olympics, but people hardly know that the real purpose behind his learning to swim was not to become a champion.

Phelps, who was in London as a member of Olympic sponsors Team Visa to take part in the 2012 handover, has revealed that his mother made him learn to swim so that he would not drown while on holiday.

"I started swimming because my mother wanted me to be water safe. She wanted to be confident that if we were ever in a situation at a pool or beach we would be safe. Later on I got involved in competition," British tabloid The Sun quoted him as saying in the shadow of Buckingham Palace while London threw a huge party as it officially became the Olympic host city.

As regards what made him succeed in the pool, the super-athlete admitted that it was childhood bullying to a certain extent.

"Kids used to pick on me and torment me but it made me a better person," said the sports star whose hero is basketball legend Michael Jordan.

"There were days when I was on the school bus and had my baseball hat thrown out of the window. It's funny because the people who did that are now trying to come back and be friends, and it's like, 'No'," he added.

Phelps revealed that being doubted by his teachers was another reason why he worked harder and harder to prove his mettle.

"One of my teachers at middle school I can't remember his name said I would never be successful. When someone says that, I'm going to work even harder to prove him wrong. It was a dream come true to achieve something no one has done before," he said.

He further said that swimming helped him a lot overcome Attention Deficit Hyperactivity Disorder.

"I couldn't sit still, I couldn't focus. Getting in the water helped me focus and stay on track and I grew out of it," he said.

Phelps flew home on Tuesday.