The first time swimmer Michael Phelps walks in an Olympic Games opening ceremony, he will be carrying the US flag.

The most decorated Olympian of all time has been nominated as the flag-bearer for the USA team at the Rio 2016 curtain raiser. He was elected by his team-mates, a delegation of 556 athletes and the largest at the Olympic Games.

The Rio 2016 opening ceremony is 5 August at Maracanã Stadium

“I'm honoured to be chosen, proud to represent the US, and humbled by the significance of carrying the flag and all it stands for,” Phelps said, laying out the remarkable progression of his competitive career.

Phelps will compete in three individual events: the 100m and 200m butterfly, and the 200m individual medley (Photo: Rio 2016/Gabriel Heusi)

“For Sydney, I just wanted to make the team. For Athens, I wanted to win gold for my country. For Beijing, I wanted to do something nobody else had done. In London, I wanted to make history. And now, I want to walk in the opening ceremony, take it all in, represent America in the best possible way and make my family proud. This time around, it's about so much more than medals.”

A first for Phelps

Phelps has never walked in the opening ceremony, because the swimming competition typically begins the very next day and he's been scheduled to race in the past.

“A lot of swimmers don’t normally walk in the opening ceremony because swimming is the first week," he told NBC. "It’s kind of tough when for me, in the past I would swim the 400m IM [individual medley] on the first day. I get up and go right from the get-go. It’s tough to be on your legs for that long. You’re on your legs for like six or seven hours and it’s a long night."

Olympic tickets are available on the Rio 2016 portal

Phelps is the second swimmer to lead the US delegation into the opening ceremony and the fifth swimmer to serve as flag bearer. Four-time Olympic medalist Gary Hall carried the Stars and Stripes at Montreal 1976.

When he made his Olympic debut at Sydney 2000, a 15-year-old Phelps was the youngest male Olympian since 1932. Now at his fifth Olympic Games at the age of 31, he is one of the team's elder statesmen.

Phelps will compete in three individual events at Rio and could be a member of all three relay teams, giving him a good chance to take his already-staggering medal haul even higher.

But the 31-year-old Phelps, who retired from swimming after the London Games but quickly reversed that decision, has continually stressed that his desire to compete in another Olympics — and he insists this really will be the final one — has little to do with collecting more gold.

Team USA at the Rio 2016 Olympics

Phelps conceded he wasn't at his best for the London Games and didn't really want to be there. After taking a year-long break, he rediscovered his love of training and competing, sparking a desire to close his career the right way.

"This time around," Phelps said, "it's about so much more than medals."