Olympian Ryan Lochte has broken his silence about his pool race with a partying Prince Harry in Las Vegas, confirming he splashed about with the royal fully clothed.

The swimming champ was celebrating his 20th birthday party with pals in Sin City when the Brit challenged him to a water dash.

Lochte says, "We were actually at the same pool - the pool party called Xcess... I had no idea he was there and his people came over to my table and said, 'Do you wanna meet Prince Harry?'

"I walked over and I met him and I shook his hand and he said, 'Hey, you wanna go and race me...?' I was like, 'All right, I gotta go get my (swimming gear)...' He goes, 'No, we're going right now.'

"So we dove in, fully clothed and everything. Before we went in, I was like, 'Do you really wanna lose?'"

But Lochte insists he stopped partying with the prince after he beat him in the pool - and he was not part of the hotel suite revelry, during which the royal stripped off and was photographed cavorting with a mystery woman around a pool table.

Appearing on Late Night with Jimmy Fallon in America on Aug. 24, Lochte added, "All we did is race in the swimming pool; we didn't do any of the other pool encounters."