"I'm not quite a citizen of New Zealand yet, but I'm working on it. Hook me up Prime Minister, please," Sheeran said recently ahead of his 2018 tour plans here.
Ardern quickly replied with a few questions.
"I've got some really important questions for you. The first: do you like pineapple lumps? Do you even know what they are?"
She then asked: "Are you willing to wear jandals in semi-inappropriate situations? And also, do you know what jandals are?"
International media have picked up on Ardern's quiz, with Time, The Huffington Post, Billboard and The Guardian among those covering the comical exchange.
"Ed Sheeran Wants New Zealand Citizenship. He'll Have to Pass Jacinda Ardern's Test First," was Time's headline.
Billboard focused in on New Zealand's favoured brand of chocolate treat: "Ed Sheeran Asks New Zealand Prime Minister for Citizenship: 'Do You Like Pineapple Lumps?'"
And The Evening Standard wrote: "New Zealand PM responds to Ed Sheeran citizenship request with hilarious quiz."
But perhaps the best thing about the international coverage is how overseas media describe Pineapple Lumps.
"Pineapple lumps are a distinctly nostalgic New Zealand treat, a chewy chocolate-covered sweet with a sweet pineapple-flavoured soft centre, which New Zealanders often keep in the freezer," wrote The Guardian.
"For non-New Zealanders, pineapple lumps are a popular chocolate candy with a chewy, pineapple-flavored filling, while jandals are rubber sandals, also known as flip-flops or thongs, said Time.
"Pineapple Lumps are a kind of popular chocolate-covered pineapple-flavoured sweet," wrote Mashable, while The Evening Standard called them "chocolate coated pineapple sweets and a Kiwi favourite".
One fan of the exchange took to Twitter to help Sheeran pass Ardern's test.
Sheeran is set to play six stadium show in New Zealand next year: three in Auckland, and three in Dunedin.
His shows will break this year's record set by Adele for the biggest tour here by a musician.