He could be handed five-eighth and goalkicking duties on debut, but the 23-year-old insists he's as ready for those challenges as he is for the anthem.
"I don't know if my mates were aware [of his Australian heritage] but I certainly was ...
"I guess it's not something you really talk about at lunchtime rugby, is it?
"There's always a little bit of stick in there but ... everyone's been very supportive.
"I guess the world's getting smaller ... just because you're born in a country doesn't mean you're there for life.
"It's a very proud moment for me to be named and hopefully if I can impress the coaches enough this week I'll get the chance to put the jersey on."
Parents Fran and Barry shed a tear when their son was named in the preliminary Australian squad, and they're preparing to fly out if he is to debut in Newcastle.
As a New Zealand schoolboys and under-20s representative, Harris played against many of the Wallabies he now calls squad-mates - including Quade Cooper, Kurtley Beale, Rob Simmons and Rob Horne.
With Reds teammate Cooper still in the early stages of his return from a serious knee operation, and Beale and James O'Connor unavailable through injury, Harris has rocketed into contention to wear the No10 or 12 jersey against Scotland.
Harris set a Super rugby all-time record earlier this year when he booted 24 straight successful shots at goal - and he's now on a new streak of 15 consecutive goals.
"[Goal kicking] is one thing I'd definitely put my hand up for ... I've put the hard work in."
- AAP
