While she grew up with her family firmly entrenched in the sport, John Hamilton admits he and wife Viv "couldn't really believe it" when daughter Grace let them know she was playing rugby during her 12-month university exchange in the US in 2013.
Even though rugby runs in the Hamiltons' blood Grace's main reasoning behind taking the game up was to try and make some friends abroad, so if you'd told John then his daughter would eventually captain her country he'd have probably laughed at you.
Now, just six years on, he and the family are getting ready to make the trek to Newcastle's No.2 Sportsground to watch Grace do just that for the first time, in her Wallaroos' Test against Japan on Saturday afternoon.
I don't think anyone ever really expects their kids to play for Australia, let alone captain their country, it's very special.John Hamilton, on daughter and Wallaroos captain Grace
"No, we couldn't really believe it when she said she'd joined the rugby club in America. I know Viv was a little bit worried about her getting hurt, but I think she was just as worried about whether she was insured to play over there," John laughed.
"Actually Viv's still a little bit worried about her getting hurt, Grace does get bashed around a bit but she's been lucky with injuries, touch wood it stays that way.
"You always want your kids to do their best but I don't think anyone ever really expects their kids to play for Australia, let alone captain their country, it's very special and we're all very, very proud of her."
That, the family's support, is something Grace herself as always highlighted as a source of inspiration too.
The Hamiltons are a constant in the crowd when the 27-year-old back-rower takes the field, whether that be for Sydney University in the Jack Scott Cup, the NSW Waratahs in the Super W or in a Test Match for the Wallaroos.
They had no hesitation in dropping everything to cross the Tasman when Grace was an 11th hour call-up for the Wallaroos' 2016 clash with New Zealand at Eden Park, as history tells us she made her first international appearance that day.
"Before her debut at Eden Park she got the call and only had a couple of days to get over there, so we thought 'well, we better get over there too'," John said.
"There was no guarantee she was going to play, but we obviously wanted to be there for her if she did debut and that was actually quite emotional for all of us, getting to see her run onto Eden Park in Australian colours."
There's no doubt there'll be a whirlwind of emotion again on Saturday afternoon too because, simply, seeing Grace make her captaincy debut will be a once-in-a-lifetime opportunity for everyone.
As per usual it won't just be John and Viv on hand either. Grace's grandmother Irene Sticka will be at Newcastle's No.2 Sportsground as well, as will older brother Harry and his fiancee Ally Tolmie.
Leesa Ronald, the eldest of the kids, has cut a holiday short to make sure she's there, although her husband Ben and son Eddy won't be able to make the trip.
"We always make the effort to go and watch her play where we all can, and support her. It's nice to get the family together to do that," John explained.
"We're really looking forward to watching her on Saturday, we can't wait to watch her lead the side out as captain
"They'll be good too, these Tests. They give the Aussies more rugby obviously but they've got two Tests against New Zealand later in the year too and they've definitely got the capability to beat them, so a couple of games against a good Japan side will be good for them."
John's seen plenty of rugby in his time too, he's coached countless Central West and NSW Country Rugby Union sides and his standing in both organisations borders on legend status.
But there was no real watershed moment for him with Grace, no particular instance when the realisation hit him his daughter might have something very special, the rarest of talents.
"She'd been playing for about two years before I even watched one of her games," he laughed.
"She came back from the US and kept playing once she got back with her university side and I, honestly, didn't know that much about women's rugby.
"I thought it would just be a bit of hit-and-giggle really but Grace's side made the grand final and I thought 'well, we better go and have a look at this'."
Grace's Norths-Uni Owls won that ACT Rugby Women's grand final and she was arguably the best on field, but even so, John still wouldn't have predicted her success after moving to Sydney the following year.
"Grace was definitely one of their leading players that day and even then the rugby was very good," John said.
"A lot of the girls had played netball and touch footy and other sports and the skills did translate. After that she was working with NSW Rugby with the development officers there and I know (Waratahs Super W coach) Matt Everard and a couple of others did a lot with her there.
"She's gone on with the Waratahs and that Super W competition is really great for women's rugby, so is giving the Wallaroos a few more Test matches as well."
On Grace's future, considering she's still just 27 she has plenty of time left in the game, John was succinct.
"Whatever she does we'll always be very proud of her," he said.
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