Boxing: Sonny Bill Williams set to make surprise return to the ring

Sonny Bill Williams will make his return to the ring on Saturday night against Waikato Falefehi (2-14).

The former All Blacks star has been training in secret before resuming his boxing career, according to The Daily Telegraph.

The fight against Falefehi ends a six-year exile from the boxing ring. Williams' last fight came against American Chauncy Welliver in January 2015, which the Kiwi won via unanimous decision.

The 35-year-old will fight at the Townsville Entertainment Centre, and will look to increase his boxing record to 8-0. The fight will take place on a card headlined by Mark Flanagan and Ben Kelleher facing off for the vacant Australian cruiserweight belt.

The heavyweight will no doubt have seen the success of fellow rugby-star-turned-boxer Paul Gallen (11-1-1) both in the ring and financially, with the Sharks legend raking in $1.275 million for his troubles against Justis Huni.

Sonny Bill Williams is set to make his return to boxing this weekend. Photo / Photosport

Williams' bout against Falefehi represents somewhat of a yardstick so he can measure how much ring rust he's accumulated in his time out of the ring, before a potential push for a fight against the former Blues captain.

Gallen has made no secret about wanting to fight Williams in the past, either. When asked last year about what the likely outcome of a battle between the two would be, Gallen was crystal clear.

Gallen said: "Would I beat Sonny? Yes."

"It'd be a good fight; he's a big guy with some experience under his belt. But I know that with the pressure I put on, if he can't get me out of there in the first few rounds I'd come over the top of him and wear him out."

Williams even confirmed he'd be willing to fight Gallen during an appearance on Channel 9's 100% Footy in August last year.

Gallen was also on the show, and quizzed the former Roosters forward whether he'd be willing to go toe-to-toe with him.

Williams responded: "100 per cent."