On Wednesday morning, Ardern, 40, revealed on Coast Radio she and Gayford, 44, would wed after two and a half years of engagement.
“We have finally got a date. Finally,” she said, declining to reveal the precise date, but adding it would be “this coming summer”.
“When I say we’ve got a date, that doesn’t mean we’ve told anyone yet. I feel like we should probably put some invites out!”
Weddings by heads of government are relatively rare.
When UK Prime Minister Boris Johnson marries his fiancee Carrie Symonds, as he intends to do this year, he will become the first British leader to do so in office in almost two centuries.
While Ardern’s wedding timetable has been set, the scale and size is not yet clear.
Ardern is well known to count international celebrities – including members of Britain’s Royal family – as personal friends.
Her popularity both at home and abroad prompts persistent questions about her relationship, her wedding and whether or not her two-year-old daughter Neve may get a brother or sister.
She and her office keep a tight rein on her private life, usually shunning questions that stray from her role as prime minister.
In the past year, she has also firmed up a practice of declining all internationally-based media requests, save for a few Australian television appearances last month when the trans-Tasman bubble was confirmed.
Since her election win, Ardern has decided to conduct more light-touch interviews with FM radio stations and magazines, which tend to stray into the personal.
In a long-form interview with Kiwi magazine Thrive, Ardern revealed she got through last year – managing New Zealand through the COVID-19 pandemic and winning October’s election – on a simple diet.
“I live on cups of tea to be honest and blimmin bliss balls,” she said.
“My mother made so many bliss balls for me during the election that I was being powered by dates.”
Gayford is a radio and television personality, who hosts fishing program Fish Of The Day, while acting as Neve’s primary caregiver.
“Thank God Clarke is a morning person,” Ardern said to Thrive.
“I don’t think I’ve talked about this before but he has consistently been the night and morning person for our daughter.
“He will bring me a cup of tea every morning without fail. Which sounds like its a little thing but it’s not.
“He’ll make me breakfast if I’m in a rush. He checks I’ve eaten before I’ve gone out the door and he checks in on my day.
“He knows the bits I find hard and he’ll send a nice little text before I go into it. He’s always thinking of me.”