Pat Pellegrini, a first five-eighths with the rising Coventry club in England, has been bought out of his last year of contract with the side to join Moana Pasifika.
The Sydney-born Tongan 25-year-old played at last year's Rugby World Cup, making his mark with a try against the world champion South Africa side.
Pellegrini had two seasons with Coventry and was the top points scorer in the Championship.
He told Coventryrugby.co.uk, "Coventry is a great club, and I've had two brilliant years there. The club has been massive in my development.
"The experience of going full-time with them will make this transition into top-level rugby much easier.
"The Championship is a really good stepping-stone into top-level rugby. It is a league crammed full of talent and playing with and against players of that standard week-in, week-out has helped me develop."
The chance to play in the leading southern hemisphere competition and to be regularly in front of Tonga's selectors was a chance too good to miss.
Coventry coach Alex Rae said while sorry to see Pellegrini depart; it was encouraging for their programme that it could produce players for the Super Rugby level.
"We will all enjoy following Pat's career and hope to see plenty of him in both Super Rugby and with Tonga in future World Cups.
"He has performed brilliantly for us."