He earned a Four Nations nod and turned 20 on the flight over but was a non-playing squad member.
O'Sullivan could not wait for NRL fans to see what Burgess could do in the tricolours.
"I went over to England and watched him play - I have very high hopes for him.
"He will toughen up as he gets older but his speed, presence, athleticism and try scoring ability is already top shelf."
O'Sullivan said an NRL switch was not a hard sell after Burgess scored against the Roosters in the 2014 World Club Challenge clash in Sydney.
"He had such a good time at Coogee during the World Club Challenge, the place sold itself," he said.
Burgess will be the latest high-profile Super League player to make the NRL switch.
Canberra will this season welcome Hull KR hooker Josh Hodgson after he featured in England's Four Nations squad that boasted another seven NRL-based players.
- AAP