The prolific winger, 30, has agreed an improved and extended contract that will see him stay until the end of 2022, in all likelihood making him a one-club man.
Huddersfield-born McGillvary, shortlisted for the Golden Boot as the world’s best player last year, said he was “over the moon” to commit further.
His decision to stay is not only a boost for Giants but Super League as well given there was plenty of NRL interest in his services.
That was one of Thewlis’ reasons why he though McGillvary - who scored ** tries to help reach the World Cup final last December - should be considered for one of the “central contracts” that have recently been introduced by the governing body.
“Jermaine was without a doubt the star of the World Cup from an England perspective and came back to us with an enormous profile which we’d hope to see further enhanced in the series with New Zealand,” he said.
“We were aware that NRL clubs had been sniffing around and we all understand the salary cap differentials in play can make retaining players difficult.
“Our budgets and cap had been fixed by this point so we did approach the RFL to help Jermaine by making him one of their centrally funded players which seemed to us an obvious fit as he had clearly done the majority of the media/promotional work down under and was both “the story” and “the face of England RL” alongside his wonderful playing performances.
“The request for financial support for Jermaine (which is enjoyed by other players and clubs) was not forthcoming and so the burden fell solely upon us.
“We were able towards the end of the season to both improve and extend Jermaine’s contract with us which was great news for all concerned and
I am sure will be well received by the supporters.”
McGillvary has scored 151 tries in 203 games for the West Yorkshire club and is expected to feature in the three Test series against New Zealand that starts later this month.
“I’m over the moon to re-sign with the club,” he said.
“The club and supporters mean everything to me.
“ It’s my hometown club and I’ve never wanted to leave as long as everything is in the right place.
“The club has always treated me well, especially (owner) Ken (Davy); they’ve always treated me well and that’s why I play so hard.
“As long as I feel loved, I’ll do anything for the club.
“It’s the same with the fans; they’ve always shown a huge amount of support and love.
“It just makes my time here a lot more enjoyable and it makes me want to stay here for the remainder of my career and even after that if there’s an opportunity.”