Born and brought up in Townsville, the 22-year-old flyer has yet to set foot in Wales but she will don their famous red and white shirt on Friday for a round two World Cup clash against Samoa.
"It will mean more than words can describe," Williams, whose father hails from the Welsh town of Prestatyn, said on Thursday.
"I haven't actually been over to Wales yet, but I'm really keen to go and meet that side of the family."
This year's tournament marks the first time Wales have qualified a women's squad to the World Cup.
In a bid to boost his side's chances, head coach Tom Brindle scoured the NRLW for players with Welsh heritage.
As well as unearthing Williams, Brindle's efforts led to a call-up for Canterbury captain Tayla Preston, who qualifies through her maternal grandfather.
For Williams, whose father worked in the military and was transferred to Australia where he settled, the World Cup call has brought a voyage of discovery.
"I opted in straight away," she said.
"I always wanted to represent my dad … and it's been a really good experience learning about my culture and Welsh heritage."
She has only met her father's side of the family via online video calls, but her relatives will tune in on Friday morning in the UK (5.45pm AEDT) to watch the clash between Wales and Samoa at CommBank Stadium in Sydney.
Despite the family ties, it could be a tough watch for the Welsh.
Although they were crushed 40-0 by Australia in the opening round, Samoa go into Friday's match as firm favourites after Wales fared even worse in a 70-6 belting by England.
"You know, it's hard to lose against England, but I reckon we'll pull together," Williams said.
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