Williams himself played for North Harbour against the 1993 Lions, while Mills, a midfielder who reached All Blacks trial level, was at No 12 for the 1983 Auckland team which edged the Lions 13-12 thanks to a late Grant Fox dropped goal.
The Barbarians played the Maori in Whangarei in 2010 to mark the Maori rugby centenary and the opening of the revamped Toll Stadium, and there are more than a dozen Barbarians members who live in the province. The Blues played an unofficial match against the Barbarians in Whangarei in 2014.
"Having it in Whangarei brings it back to provincial and grassroots rugby and we think that's great for us and the game," says Williams.
The thinking behind the make-up of the team is that it gives those provincial players a crack at the Lions who would otherwise not have done so, given the remaining fixtures are the tests, and clashes with the Super franchises plus the Maori All Blacks. There will also be a special jersey made, though due to the clash of colour with the Lions, it will be white, not the traditional scarlet Barbarians kit.
The Lions have played the NZ Barbarians' UK counterparts in the past (2009) and that club enjoys a much higher profile due to more big TV games.
The Barbarians received the green light some days ago and Williams announced the news on Friday night to patrons at the Barbarians' Eden Park clubrooms.