The previous ceiling of $1.4 million was set by Aaron Mooy’s switch from Melbourne City to parent club Manchester City.

The City Football Group were planning a similar pathway for the precocious Bos, who last month made his Socceroos debut against Ecuador.

CFG aimed to keep Bos under the umbrella to further build his value as a transfer commodity, bringing him initially to the Eithad before loaning him out.

However, the management team guiding the future of the Melbourne City left back - earmarked as the long-term replacement for Aziz Behich in the green and gold - had other ideas, with Westerlo prepared to stump up $1.6 million to sign Bos on a multi-year deal.

The belief is that Bos will thrive in a highly technical league at a club which currently sits in the European Conference League qualification spots, with an outside chance of finishing high enough to grab a Europa League berth.

Bos holds a Dutch passport through his father, making the European move seamless for a player believed to be among the brightest of his generation.

He has made 37 A-League Men appearances in total for the back-to-back premiers, 24 this season alone, his attacking prowess and vision setting him apart from his domestic peers..