Smith denied then he was on the brink of rejoining the All Blacks after his stints with the team as technical adviser (1998-99), head coach (2000-2001) and assistant to Graham Henry (2004-11), but the offer was always going to be hard to turn down.
"When I was asked to be involved in the All Blacks again for 2015, it was a case of checking whether I had the support of my family, which I did," Smith said. "I also spoke to some of the senior players in the team and everyone was incredibly supportive. I care deeply about the All Blacks. I'm excited to be back and looking forward to getting stuck into next year."
A New Zealand Rugby Union statement last night said Smith will be stepping down from an official coaching role with the Chiefs, but will still work from the team's base and continue to coach once a week to keep his hand in. He will also be working with all five of New Zealand's Super Rugby teams during the season in his All Blacks capacity.
Hansen, who paved the way for Smith's return when shifting assistant Aussie McLean from defence to an analyst role, said he was delighted to have the services of his old mate.
"He is one of the most astute coaches in world rugby and, having worked with him in the past, we know just how valuable he is to any team he's involved in," Hansen said.
"Smithy will add another dimension to what is already a strong coaching group in what will be a big year for us. We look forward to welcoming him back into the fold.
"Smithy's role will be purely around defence but, as we do with all our coaches, we will tap into his vast knowledge of other areas of the game."
Chiefs chief executive Andrew Flexman said: "The Chiefs are committed to providing as much support as possible to the All Blacks in their quest to win back-to-back World Cups, so we support Wayne 100 per cent in his decision to assist the All Blacks and appreciate the massive contribution he has made to the Chiefs."
Toulon owner and president Mourad Boudjellal yesterday confirmed that All Blacks midfielder Ma'a Nonu will join the club after next year's World Cup on a two-year deal. The announcement came days after Dan Carter said he will join Paris rivals Racing Metro on a three-year deal.