The 28-year-old last played for the Kiwis in the 2008 Anzac test, just weeks before he walked out on the Bulldogs and made the switch to rugby union. It was a match that also marked Stephen Kearney's first as Kiwis coach.
Williams has played seven tests for the Kiwis but never won - six defeats and one draw - but that's likely to change when the tackle Samoa in Warrington.
They should have far too much firepower for Samoa, who have endured a difficult buildup with a number of big-name players unavailable.
Kearney has named a powerful New Zealand side in expectation of a physical match but he also hopes to feed of the Roosters' success in winning this year's NRL grand final, naming all five in the side along with Manly's Kieran Foran.
It means first caps for exciting winger Roger Tuivasa-Sheck and prop Sam Moa, who will start off the bench, and a recall for Frank-Paul Nu'uausala.
"It's an important game but I thought it was important to capitalise on the energy the Roosters boys had and the momentum they created for themselves over the last little period," Kearney said.
One of those is Williams, who has been the talk of the World Cup even before the tournament has kicked off. It's something he's been used to throughout his career, and he handles the attention well, but the player is determined to fit in with the team.
"I just do what I do, keep it humble, work hard, do all my extras, tick all the boxes and try to gain, first of all, my team-mates' respect by doing all those things you don't see on TV and everything that happens above that is a bonus," he told reporters after training in St Helens.
"This week [against Samoa] will be no different. I'll try to base my game on hard work."
It will be exactly what Kearney wants to hear. The Kiwis coach has built a simple gameplan based around solid defence, completing sets and a low penalty count. It doesn't mean players will be restricted in what they can do, especially someone like Williams who can make the audacious look routine.
"It's quite obvious the talent he has but I think he brings a bit more than that," Kearney said. "He brings a sense of confidence to the people around him.
"I could talk about the intricacies of his talent and what he can do with the footy but, in essence, he has a job to do in this team and understands his role. For a guy of his stature, he understands that he has to get down and dirty sometimes and that's a good quality to have."
Williams will play in his usual position on the right edge, meaning captain Simon Mannering will play down the middle as a back-rower. Elijah Taylor will provide back-row cover off the bench and he also see action at dummy half if hooker Issac Luke needs a spell.
Thomas Leuluai has been struggling with a sore groin and won't be risked against Samoa. Scans have shown there's no tear or strain and there are hopes a cortisone injection he received earlier in the week will help settle the injury and see him fit to play next weekend against France.
Samoa are considerably weaker than the side many expected them to field at this World Cup with the likes of Roy Asotasi, Steve Matai and Jeff Lima missing for various reasons but Kearney has still labelled if a "red flag" match.
"I don't buy into any of that talk [of them being weak]," he said. "For me I look at their side and who they have, like Reni Maitua, Anthony Milford and David Fa'alogo rather than who they don't have."
New Zealand team to play Samoa at Warrington on Monday morning (7am NZT): Josh Hoffman, Roger Tuivasa-Sheck, Dean Whare, Bryson Goodwin, Manu Vatuvei, Kieran Foran, Shaun Johnson, Jared Waerea-Hargreaves, Issac Luke, Jesse Bromwich, Frank Pritchard, Sonny Bill Williams, Simon Mannering. Interchange (two to be omitted): Elijah Taylor, Sam Kasiano, Sam Moa, Frank-Paul Nu'uausala, Greg Eastwood, Ben Matulino.
