When Erin Mortimer steps onto Accor Stadium to sing the national anthem before State of Origin III, she will be carrying with her the legacy of one of New South Wales' most iconic rugby league moments.

It has been 40 years since her father, Steve Mortimer, captained the Blues to their first Origin series victory in 1985, famously kissing the SCG turf in a moment that still stirs deep emotion among NSW fans.

Now 68 and living with dementia in a Revesby nursing home, Steve won't be able to walk Erin onto the field.

Speaking with Newscorp, his daughter says the occasion will be a powerful tribute to her father and to the team he once led with such spirit.

โ€œIt will be a little bittersweet that he can't walk me out but I will be dedicating that anthem to my dad and all of NSW. This being a game three decider, it's going to be electric. Let's just hope we have a win.โ€

Erin has sung the anthem on the Origin stage before, in 2008 and again in 2013, but says this one carries extra emotional weight.

โ€œGiven what dad is going through, I'm grateful and privileged,โ€ she said.

โ€œThose images of him being lifted up on his teammates' shoulders and kissing the SCG turf will be rolling around in my mind when I walk onto the field.โ€

She says her father remains in good spirits and that family visits have become even more meaningful.

โ€œDad is happy, comfortable and relaxed,โ€ she said.

โ€œBringing our kids, dad's grandkids, to see him is very important because of that face-to-face connection and engagement. It sparks joy.โ€

Steve Mortimer played nine Origins between 1982 and 1985, culminating in that historic series win under coach Terry Fearnley. His legacy as one of the state's great playmakers and leaders remains etched into the folklore of Origin.

Erin, a performing arts tutor, will also release a new sports anthem titled Play The Game, a project she says celebrates the broader spirit of competition and camaraderie in sport.

For all the pre-match spectacle that Origin brings, this moment will stand out for its quiet resonance.

โ€œThe adrenaline, nerves and anticipation before kick-off will be amazing so I can only imagine what dad was feeling 40 years ago,โ€ Erin said.

โ€œI'm very excited, humbled and honoured on a personal note but also the sense of occasion.โ€