Sonny Bill Williams will benefit from playing England in his All Blacks Test debut, Wallabies star Quade Cooper says.

Williams has surprisingly been named at outside centre to play his first rugby Test for New Zealand in Saturday's (0100 Sunday AEDT) match at Twickenham.

The former Canterbury Bulldogs star and Kiwis rugby league international has been fast-tracked into the All Blacks set-up after controversially switching codes in 2008.

He has said he always harboured a desire to pull on the All Blacks jersey.

"Playing against the English will work very nicely for him," Cooper told reporters as Australia prepared to face Wales in Cardiff this weekend.

"They're very direct and the way that he hits and plays, it could be a great outing for him.

"I hope he goes well but, at the same time, the All Blacks are trying things and going to try different combinations so you might see him at 12 (inside centre) as well.

"He's a big boy and very skillful so it's going to be interesting for international footy.

"Test match footy is another step up so it will be interesting to see how he goes."

Williams is still inexperienced in the 15-man game, having played two injury-affected seasons with French club Toulon, an international against the Wallabies with the Barbarians and a handful of provincial games in New Zealand.

But his improvement has meant All Blacks coach Graham Henry was keen to include him on the side's grand slam tour.

Veteran Wales outside centre Tom Shanklin said Williams represented a new breed of backline giant.

"There's a new era of players coming through, there's Sonny Bill, we've got a couple here, George North and Jamie Roberts, guys who could probably play in the forwards as well as the backs.

"He's a very good player. He's big, he's fast and he's got very good skills as well."

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