'Overrated pretty boy' David Nyika ripped as fight confirmed for Sonny Bill Williams vs Paul Gallen card

Nik Charalampous ripped fellow Kiwi David Nyika as an "overrated pretty boy" as their matchup was confirmed on the Sonny Bill Williams vs Paul Gallen undercard on Wednesday.

Nyika, an Olympic bronze medallist and two-time Commonwealth Games champion, is returning to the ring for the first time since being knocked out by Australia's Jai Opetaia in January.

It was the 29-year-old's first loss as a professional (10-1) and he is aiming to get things back on track against Charalampous (23-6-2), a cagey but limited veteran who is undefeated in his last four outings.

Sonny Bill Willams vs Paul Gallen at Sydney's Qudos Bank Arena on July 16 is available to order live and exclusive on Stan Pay-Per-View for $70

Nyika was a flagbearer at the Tokyo Olympics and has a high profile in New Zealand - partly because of his good looks.

"I think Nyika is an overrated pretty boy," Charalampous - nicknamed 'Nik the Greek' - said ahead of the July 16 fight at Sydney's Qudos Bank Arena.

"One of us went 10 rounds with Jai Opetaia, the other got stopped. I'm ready to go hard!

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"David has had everything handed to him on a platter. He's got good genes, he's 6'6, but when he first stepped up to fight adversity, he went to sleep... I know he thinks I'm going to be an easy comeback opponent, but it's not going to go down like that."

Nyika was stopped by Opetaia in the fourth round of a brutal slugfest.

"I'm ready. My journey restarts here," Nyika said.

"Fair play to Jai, he was the better fighter on the night. But true champions get back up again when they get knocked down – and I have no doubt I am going to be world champion."

The Williams vs Gallen headline act is also making waves across the Tasman as a decade of trash talk finally gets real in the ring.

"It's pretty clear these two don't take a shine to each other," David Higgins of co-promoter Duco Events said.

"They're both incredible athletes – but very different people.

"This fight – which we're thrilled to be bringing to Kiwi sports fans... has all the magic ingredients for an epic showdown.

"It's New Zealand versus Australia - two legendary household names and serial winners looking to bookend their incredible sporting careers with one final victory.

"It's a huge, huge fight on a night that will also see the New Zealand's most exciting prospect David Nyika return to the ring – an event not to be missed."

Australian bookmakers have installed Williams as a slight favourite.

Gallen boasts the superior boxing pedigree, having fought the likes of genuine heavyweight contender Justis Huni and KO'd former world title holder Lucas Browne, alongside victories over fellow NRL stars including John Hopoate, Justin Hodges and Darcy Lussick.

But Williams is four years younger at 39 and boasts a massive height and reach advantage.

"It's genuinely impossible to pick a winner," Higgins said.

"It's finally time to find out who really is the better man."

Tale of the tape

Sonny Bill Williams

Born: 3 August 1985 (age 39) in Auckland

Height: 191 cm

Weight: 108 kg

Record: 9-1 (4KO)

Former NZPBA heavyweight champion, two-time Rugby World Cup winner, Two-time NRL Premiership winner, Super Rugby champion, 2016 Olympian with the New Zealand sevens team.

Paul Gallen

Born: 14 August 1981 (age 43) in Sydney

Height: 180 cm

Weight: 102 kg

Record: 15-2-1 (8KO)

2016 NRL premiership winner with the Sharks, captain of NSW State of Origin team, Rugby League World Cup winner in 2013 with the Kangaroos, three-time Dally M lock of the year, sixth on NRL all-time appearance list (348 games).