“I love winning, I love the high-pressure environment. I don’t know if I could get that overseas,” said the 30-year-old.

While his athletic prowess is unquestioned, some labelled Williams a dilettante before for only signing one-year deals that let him flit between rugby union, league, sevens and even professional boxing.

The three-year contract is his longest commitment to the All Blacks and coach Steve Hansen said it would give him the chance to etch his name in union’s honour roll.

“He’ll only get better and better. He could end up being one of the greats of our game,” Hansen said.

Under the deal, Williams will switch his Super Rugby allegiance from the Waikato Chiefs to the Auckland Blues, coached by former All Black great Tana Umaga.

“It’s no secret that Tana and I go way back,” said the 33-test centre, who worked with Umaga at Toulon when he first shifted to union in 2008 then again at Counties Manukau in 2014.

“I feel like I’m coming home,” added Williams, who was a member of New Zealand’s 2011 and 2015 World Cup-winning squads.

During his much-travelled career, Williams has won both the Super Rugby title with the Chiefs and the Rugby Championship with New Zealand.

In rugby league he won Australia’s NRL twice, with the Bulldogs in 2004 and Roosters in 2013, and also triumphed in all seven of his professional heavyweight boxing bouts, even winning the New Zealand title in 2012.

He was used mostly as a bench player in the 2011 World Cup but blossomed in the 2015 campaign and was an integral part of the Richie McCaw-led team’s success.

With top players such as McCaw, Dan Carter, Conrad Smith and Keven Mealamu now gone, the All Blacks are rebuilding for their 2019 Cup defence in Japan.

The departure of Ma’a Nonu, in particular, gives Williams the chance to become New Zealand’s premier inside centre.

He said Hansen approached him late last year about being part of the leadership group that will steer the new-look team’s 2019 campaign under skipper Kieran Read.

“He’s a freakish athlete and is one of the best, if not the best in the world in his position. We saw at the World Cup how he made a difference every time he played,” Hansen said.

“He now has a really big role for us coming on board for three years to develop other people around him.”

Williams’ contract allows him to pursue his interest in boxing, which he said provided an invigorating change of training routine from rugby.

He said moving from the Chiefs to the Blues was a difficult choice but he wanted to be close to his Auckland-based extended family.