Sonny Bill Williams shows off new revolutionary training regime ahead of league return

Having confirmed his return to rugby league, now-former All Black Sonny Bill Williams has opened the doors into his rigorous training regime ahead of his comeback to the 13-man code.

Williams, 34, last month signed on with Canadian-based UK Super League side Toronto Wolfpack, as the club looks for a high profile debut campaign in the northern hemisphere's premier competition.

The deal makes Williams the best paid player on the planet, taking home $10 million over his two-year contract.

Based in the Australian town of Kingscliff, Williams is operating out of Surfina Australia's high performance centre.

His preparation for his league return has been far from orthodox, with trampolining and gymnastics all part of his new regime.

"The finished product is the big lights," Williams told Nine News.

"You earn that right through that week, through that pre-season. Behind closed doors, when you're at home doing your stretching, eating the meals you probably don't want to eat, that's how you get to that point."

Williams is working under trainer Keegan Smith, son of former Roosters coach Brian, a revolutionary in dieting as well as strength and conditioning.

Smith and Williams are pulling out all the stops in preparation for the Wolfpack.

"The kind of training that we're doing, I don't think any player's ever actually done to prepare themselves for footy," Smith says.

"That opens up the possibility of getting some results that haven't been seen as well."