Now Sio and Alaalatoa will continue their family's rugby legacy when they run out for Australia in Saturday's Bledisloe Cup test in Sydney.
And their fathers could not be prouder.
"It's one of those things you never dream of but for the two families, it's very exciting," Tavita Sio said.
The young pair grew up playing junior rugby together in the western suburbs of Sydney.
"We can't wait to get out there and support Allan, Scott and the Wallabies team," Vili Alaalatoa added.