Saracens wing Williams will reach the half-century landmark when he lines up against opponents Tonga on Saturday.
It comes six years after he made his Test debut and is testament to the enduring quality he offers Wales, either from wing – his starting position this weekend – or full-back.
“It was always my boyhood dream to play for Wales,” Williams said.
“To get to 50 caps gives me goosebumps just talking about it. Hopefully, there are many more to come.”
In a reference to his pre-professional rugby playing days, Williams added: “I am just a scaffolder living the dream. I did not really think it would be possible to get here.
Liam Williams in action for the British & Irish Lions last year.
“I got my first cap in 2012, and to win my 50th cap now is one of my greatest achievements. If I do lead out the team it would be a huge honour for me.
“Any game is emotional, but I have to look at the 50th as just a number. It is not about the cap number, it’s about me putting that red jersey on and going out there and giving it everything.”
Wales head coach Warren Gatland has made 14 changes for Tonga’s visit, with only lock Adam Beard retained in the starting line-up following last weekend’s first victory over Australia for 10 years.
The likes of Williams, fly-half Dan Biggar and lock Jake Ball provide an experienced edge.
But there are also several players in the preliminary stages of their international careers such as full-back newcomer Jonah Holmes, scrum-half Tomas Williams, prop Leon Brown and flanker Aaron Wainwright, who join them in the starting XV.
“It is good we can make these changes, which are going to help us going through to the Rugby World Cup next year,” Williams added.
๐ด๓ ง๓ ข๓ ท๓ ฌ๓ ณ๓ ฟ The last time Wales faced Tonga was in the summer of 2017 ๐น๐ด
— Welsh Rugby Union ๐ (@WelshRugbyUnion) 17 November 2018
Three of today's starters - @SebDaviess, @steffevs09 and @wynjones2 - won their first caps in Wales' first win at Eden Park. (And yes, it involved some *big* hits.) pic.twitter.com/wPQOSqU8VZ
“It would be awesome to get a win under our belts, and then the big one next weekend against South Africa and try to finish off with another victory.
“As a squad, we are in a good place, and that is only going to work well for us leading into the World Cup.
“We know what they (Tonga) are. They are a big-hitting team that like to throw the ball about, so we have to be aware of that.”
Williams, meanwhile, has settled seamlessly into life with Premiership champions Saracens, having joined them from the Scarlets last year.
And with British & Irish Lions Test honours also in his portfolio, life is good on all fronts for the 27-year-old.
“I am going to take the third year at Saracens, which takes me up until the season after the World Cup,” he said.
“Moving to London was a big step for me. It was a bit of a lifestyle change, sort of like starting over again, although I knew some of the guys from the (2017) Lions tour.”
