His rapid elevation to the All Blacks captaincy has drawn comparisons with Richie McCaw but for now a hug from mum is the only accolade Sam Cane needs. The humble 23-year-old was a surprise choice to lead New Zealand in their second pool game at the Rugby World Cup, against minnows Namibia in London on Thursday.

The flanker takes the No.7 jersey and skipper's armband off modern great McCaw in one of 12 changes to the team who beat Argentina 26-16.

It was expected coach Steve Hansen would turn to veteran hooker Keven Mealamu in his last campaign or possibly flanker Liam Messam - Cane's captain at the Chiefs - if McCaw and his deputy Kieran Read were rested at the tournament. However, Cane earns a status he says was unexpected, having simply targeted selection this week.

"It's extremely special to become an All Black for the first time but to be able to lead your country out is something that stands above that. I'm hugely honoured and pretty excited by it."

The best moment was when he broke the news in person to his parents, who are in London this week. He said both were overjoyed and mother Kathy delivered a cuddle over the breakfast table. Cane is New Zealand's 67th Test captain and the fifth-youngest.

Playing in the shadow of McCaw, he has only started twice in the last two seasons. Fourteen of his 25 caps have come off the bench since a 2012 debut. Like McCaw, Cane made his debut as a 20-year-old against Ireland and has gone on to showcase similar maturity and ability, crossing for nine tries despite his lack of minutes.

The captaincy has come at the same age as McCaw's first appointment in 2004, even if it is only for a one-off Test. Hansen says the promotion is more about future-proofing, with McCaw likely to retire after the World Cup and be replaced as leader by Read.

"If something happened to Reado next year and he wasn't available then we've got a guy who's actually had a go at it," Hansen said. "Sam's time around Richie has been good in that he's had to think about the whole team, not just himself."