NEW ZEALAND rugby superstar Sonny Bill Williams will at last face a "real" boxer, says South African heavyweight veteran Francois Botha about their impending 10-round bout in Brisbane, Australia.

The multi-talented Williams, who has five wins out of five fights under his belt, is at present in Japan finishing off his rugby union career before moving to Australia next year to continue his rugby league career.

But he may no longer have a jaw by then, if the White Buffalo's threat to "hit him hard" is to be believed.

"I've always seen him as a fighter in the few fights that he's had, but he's in for a rude awakening," Botha said.

"He's going to get hit harder than he's ever been hit. 'White Buffalo' is in a different league; he's been fighting garbage cans so let's see what he can do when he has a real fight in front of him.

"I won't knock him out in the first round, I want the [internet] live stream to catch up; I don't want the viewers to log in and find out the fight is over."

The Brisbane Entertainment Centre, where the November 24 fight will take place, was the same venue where 27-year-old Williams made his debut, knocking out countryman Gary Gurr.

Botha said his age, which would be matched by Williams' athleticism, would not be a factor, despite suffering three successive defeats in his last three fights, the last of which was at the hands of German Francesco Pianeta on points.