The two retired NRL premiership stars have been on a collision course to square off in the ring ever since Gallen made his debut with the gloves in 2012, and football fans begged for the bout to happen.
Williams has since been accused of dodging Gallen, and last year the latter conceded the cross-code event that was little chance of happening.
Williams had his first fight in 2009 and has only had eight in total, although has won every one of those.
In June he had his first fight in six years, defeating Waikato Falefehi by unanimous decision.
Gallen has been much more prolific, holding an 11-1 professional record with his only loss coming in a 10-round battering against Australia’s superstar heavyweight Justis Huni, also in June.
It was Gallen's second fight this year already, having annihilated former heavyweight champion Lucas Browne in a stunning first-round knock out.
Despite being urged to retire following the Huni slugfest, Gallen recently signed a contract to have three fights over the next 18 months, although his opponents are yet to be announced.
Williams was asked on ABC Radio whether he would be up for stepping in the ring with Gallen.
"I hope you weren't insinuating that he's out of my league, because for myself I definitely don't believe that," Williams said.
"He'll be all part of the process. For me it's the challenge.
"I don't need to fight and he's stated that he's a prize fighter so he's obviously in it for the money. For me, I'm in it for the challenge."
Gallen has repeatedly stated he is in boxing solely for the money, and he was rumoured to have pocketed more than $1.2 million from the Huni fight alone.
Gallen also raked in a sizeable pay cheque for throwing down with retired AFL star Barry Hall two years ago in Melbourne, which ended in a draw.
But a fight against Williams would undoubtedly net both men the biggest single payday of their sporting careers, with speculation each could pocket upwards of $2 million for the event.
Williams, though, isn't about to jump in the ring with Gallen - or Hall - without some more preparation under his belt.
Now fully retired from football, Williams says he wants to commit himself to the sport for two years.
"When it comes to fighting Paul Gallen or Barry Hall, those guys are all part of the process but for me it's about the daily grind and being wholeheartedly in it," Williams told the ABC.
"That stems from something more than say, 'I've got my eyes on solely focused on Paul Gallen or Barry Hall'.
"I'm just trying to lock in something. I've had a lot of offers already to fight overseas.
"But at this stage, it's just getting back in the ring, getting a feel for it, training hard day in day out. And then I think god willing, if I reach the heights that I think I can reach, those guys [Gallen and Hall] will be part of the process.
"I've given myself 24 months... I've given my all to rugby and rugby league over the years and it would just be nice to see where I'm at [with boxing] after 24 months instead of a six-week camp or a 12-week camp."