Sonny Bill Williams has several championship titles to his name: he is a two-time Rugby World Cup winner and was even New Zealand’s heavyweight boxing champion.

He hopes to add the title of Olympic gold medallist to his list of accomplishments at Rio 2016 where rugby sevens is set to make its Games debut.

Williams, who celebrated his 31st birthday in Rio on Tuesday, became an international star after he helped New Zealand’s famed All Blacks to back-to-back Rugby World Cups.

Sonny Bill at Rio 2016  would be ‘awesome’ says New Zealand captain

Williams decided to make the switch to the faster pace of rugby sevens in January.

“The key was putting myself in the sevens environment through the whole year to learn from all the boys up here,” Williams said at a press conference in Barra Olympic Park on Tuesday.

"The fitness levels are up where they should be, the knowledge of the game is up there as well."

Williams is greeted by fans in the Olympic Village on Wednesday (Photo: Getty Images/Ryan Pierse)

Head coach Sir Gordon Tietjens says he has seen Williams’s game evolve since he joined the sevens side.

“He’s picked up the game tremendously well,” Tietjens said. “If you see him play sevens now, he’s got a real understanding of how the game should be played.

“You ask him personally, he’s in the best shape of his life. His speed has gone up.

“I wouldn’t be surprised if this is not the last sevens tournament he plays in. Perhaps he sees sevens down the track as an opportunity to get himself right for the 15s.”

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Williams has worked hard to adapt to rugby sevens (Suhaimi Abdullah/Getty Images)

Tietjens says if Williams and the All Blacks succeed in Rio, it could inspire more players to make the switch from 15-a-side rugby to sevens.

As for Williams, he plans to make the most of his Olympic experience. In his spare time, he hopes to watch New Zealand Olympic shot put champion Valerie Adams compete as well as New Zealand's women's rugby sevens side, which includes his sister Niall Williams.

Williams famously made headlines after giving away his 2015 Rugby World Cup medal to a young fan.

Is there a chance he might give away an Olympic medal if the All-Blacks make it to the podium? 

Williams doesn’t want to get ahead of himself.

“Got to win it first, bro,” he said.