The 27-year-old took the unconventional route to the top having left Cardiff Blues as a youngster to ply his trade in New Zealand and then Doncaster Knights before impressing for Sale Sharks in the Gallagher Premiership.
And he is champing at the bit to help Wales end their Guinness Six Nations campaign on a high this weekend.
“It means a hell of a lot to me obviously,” said John.
“It’s been a long time coming and I’m pleased to finally be able to play on the big stage. I always felt that I had the ability to play international rugby but it took a little bit longer than I expected.
“But I always thought I could do it. I’m hopefully going to bring some physicality to the side and hopefully some strong scrummaging.
“It was definitely a dream of mine to play for Wales. My dad being Welsh, my mother being English and me being born in England but growing up just half an hour down the road from here it was always a dream.
“That’s what I wanted to do since I was a five-year-old boy.”
John has gathered a reputation as a powerful scrummager in the Premiership and he believes he can do a job in the Welsh scrum against a strong Scotland pack.
He said: “He (Pivac) just said it’s a big job for me. I’m starting for my first cap in such a big game.
“He just said to do what I do week in, week out for Sale. It’s about me ensuring a solid scrum (…) You win some, you lose some and that’s pretty much all you can do but I wouldn’t say it’s been vulnerable. Dillon and Leon have both done very well, as have the looseheads.”
