Sonny Bill Williams may be undefeated in his boxing career thus-far but that's going to end on Friday, says opponent Francois Botha.
In fact the experienced South African heavyweight is so confident that he's branded ex-All Black Williams 'stupid' for fighting him.
The man nicknamed 'White Buffalo' says the step-up for Williams is so great that he should be fighting his son - a 70kg amateur boxer - in order to make it a fair contest.
"He's got a lot of big balls, and I don't mean rugby balls," Botha told Australia's Courier-Mail.
"Why is he taking this chance? He should stick to rugby because I will hit him so hard that when he tries to catch the ball, he'll just miss it.
Botha has fought world champions including Mike Tyson and Evander Holyfield during his career and although he's in the twilight of his career - and has lost his last three fights - he's a big step-up in class for Williams.
"For me in a boxing sense I need to take fights like this to move up," the former All Black said last week.
"It's definitely going to put my name out there internationally if I win because it's for a WBA international belt."
But Botha is dismissive of Sonny Bill, the boxer.
"In real life, he should never have an opportunity to fight a guy like me with just five fights to his name," he said.
"I'm only taking this fight because of his notoriety in rugby."
All that remains to be seen is whether Botha's punch is as big as his predictions.