Show us your birth certificate, parents would yell indirectly towards a nine-year-old West Harbour junior named Scott Sio, who at the time was perhaps luckily a little naive.

Because had he have been able to grasp the comments being levelled at him simply for being a bit bigger than the other kids, maybe Sio's passion for the game evaporates.

Maybe he wouldn't be a Wallaby. Maybe he wouldn't be lacing up the boots for the ACT Brumbies for a Super Rugby AU showdown with the NSW Waratahs at Sydney Olympic Park tonight.

"They're pretty confronting things as a kid, and you don't quite understand," Sio said.

MORE BRUMBIES

But today he does, which is why the Brumbies prop is among a group of Australia's top athletes joining forces for the "We Got You" campaign in an attempt to eradicate racism in sport.

"One of the main incidents I came up with as a kid, for ourselves, we're a bit bigger than other kids when we are younger and it takes other kids a bit more time to develop," Sio said.

"We had some parents from other teams saying 'where's your birth certificate? Are you really this old?' They were saying we were lying about our ages.

"For me, it's so important to protect children because children play rugby and sport because they want to play with the friends and enjoy it, it's what they love. You don't want to drown out the passion kids have, because it's the most pure kind of passion."

Sio says his story is no different to any other kid of Pacific Island origin, whether they're playing in Concord or Canberra. Spend enough time around junior football and one will realise, sadly, he is right.

"It's through no fault of their own that we are genetically a tad bigger than other kids when we are younger. No one should have to experience things like that at such a young age," Sio said.

"Racism is a learned thing, kids aren't born racist. It's things they pick up over time, things they are told about people over time.

"To be able to have a platform like this to provide solutions through engagement and exposure, it is the way forward. It's the best way to help educate people about other cultures, so there isn't that vision where they don't quite understand the other person."

So often Sio would come home from football with his parents David, a former World Cup representative with Samoa, and Tina, reassuring him "we will work through this together".

Which is why today he wants to highlight the cultural differences of Pacific Islanders as part of Patty Mills' player-led movement. Pressure can often be greeted with humour, which can be misconstrued by a coach or a higher figure. Strong ties to communities mean "when you let the team down, you really wear it ... it takes a big emotional strain".

But just as Sio told Mills, the Brumbies seem to have the right formula.

They surged onto the training field on Friday morning for a captain's run wearing shirts with an Indigenous design.

They did so under the eye of coach Dan McKellar, who knows part of what makes his squad so unique is the array of cultures coming together under one banner.

So it comes as little surprise few embraced the club's inaugural Pasifika Day last season quite as much as McKellar.

The Brumbies wore a one-off jersey design with designs representing the Maori people of Aotearoa, and the people of Samoa, Fiji, Niue, Tonga and the Cook Islands.

"Almost 50 per cent of our team is of Pacific Island heritage and I thought it was so empowering for our coach Dan to want to recognise the contributions of the Pacific Island community and a part of what makes the Brumbies so unique," Sio said.

"He took the time to learn. That's the engagement and exposure I'm talking about. Use that as a tool for players to express themselves and their culture, what they're so proud of and what they were brought up with by their parents.

"That in itself really strengthened the bonds within our team and helped give players a better understanding of their own mates in the team.

"Things they found a bit hard to ask or a bit hard to cover in one conversation, they were able to do that with an experience. You feel like you're a part of it as well.

"That's the goal, to facilitate those kinds of experiences for people. People can learn about what makes a player special, what drives them as a player, and build that personable connection between a player and a fan.

"You can bridge that gap."

SUPER RUGBY AU ROUND THREE

Saturday: NSW Waratahs v ACT Brumbies at Sydney Olympic Park, 7.15pm.

Brumbies squad: 1. James Slipper, 2. Folau Fainga'a, 3. Allan Alaalatoa (c), 4. Darcy Swain, 5. Murray Douglas, 6. Rob Valetini, 7. Tom Cusack, 8. Pete Samu, 9. Joe Powell, 10. Noah Lolesio, 11. Tom Wright, 12. Irae Simone, 13. Tevita Kuridrani, 14. Andy Muirhead, 15. Tom Banks. Replacements: Connal McInerney, 17. Scott Sio, 18. Tom Ross, 19. Lachlan McCaffrey, 20. Will Miller, 21. Issak Fines, 22. Bayley Kuenzle, 23. Mack Hansen.

Waratahs squad: 1. Tom Robertson, 2. Tom Horton, 3. Harry Johnson-Holmes, 4. Ned Hanigan, 5. Rob Simmons (c), 6. Lachlan Swinton, 7. Michael Hooper, 8. Jack Dempsey, 9. Mitch Short, 10. Will Harrison, 11. Alex Newsome, 12. Karmichael Hunt, 13. Joey Walton, 14. James Ramm, 15. Jack Maddocks. Replacements: 16. Robbie Abel, 17. Tetera Faulkner, 18. Angus Bell, 19. Tom Staniforth, 20. Will Harris, 21. Michael McDonald, 22. Mark Nawaqanitawase, 23. Ben Donaldson.