And the team at New Idea aren't the only soccer fans who have had these thoughts, with Sunrise hosts Nat Barr and Matt Shirvington poking fun at the royal.
"What we do know is there will be some very anxious Aussies watching that game - in particular one who will be torn as to who to barrack for, Australian-born Danish royalty Princess Mary," Sunrise reporter Georgia Chumbley said to Nat and Matt during a live cross.
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"She's previously faced discussions around this before when the men's Socceroos faced Denmark last year in the Men's World Cup."
"But I think that maybe she'll be barracking for Australia in her heart, but officially for Denmark," she added.
Matt then added his two cents: "Born and bred in Australia. Come on. You've gotta go back to your roots!"
Despite poking fun at the princess for not cheering on the team from her homeland, Nat did mention that she could imagine privately cheering for the Matildas when they faced off against Denmark.
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"I can see Mary sitting in one of the palaces screaming at the TV. Come on Aussie!" she said.