Pacific powerhouses – Tonga, Samoa and Papua New Guinea are confirmed to play, and for the first time, Lebanon will participate.
An additional two teams will be announced shortly, rounding out the three-match festival of rugby league.
Player representatives, Leilani Latu (Tonga) and Sauaso Sue (Samoa) joined NRL Head of Football, Brian Canavan and Campbelltown Mayor, Councillor George Brticevic for the announcement, with the Invitational to take place at Campbelltown Stadium on Saturday 23 June.