''I raised it with the Duchess because she has spoken about period poverty before. Some people consider it embarrassing or taboo, but she has lifted the lid on it and made it a global topic,'' Prime said.
''I thanked her for her work and we had a little exchange about it. When it was time for her to go on she turned around, squeezed my wrist and said something along the lines of 'keep it up' or 'you're doing great work' ... I was too star-struck to remember exactly.''
Prime said Tukau's initiative had so far seen 2400 women in Kawakawa, Moerewa and Kaikohe take up re-usable menstrual cups, freeing them from the expense of buying sanitary products.
''That's huge when you think about the financial and environmental impact, and the empowerment,'' she said.
The project had its genesis during last year's election campaign when Prime was shocked to learn how many girls were missing school every month because they couldn't afford sanitary products.
Her sister, Season-Mary Downs, launched a fundraiser and started giving away the cups, which last 10 years and normally cost $25. Women who could afford the cups gave a koha which then paid for a cup for someone who couldn't.
Prime also met Prince Harry, who had just been to Fiji and Tonga. She spoke about the lack of female representation in Pacific Parliaments while the Prince talked about the role men could play to address the imbalance.
She then cheekily asked for a high five — she'd been put up to it by her brother-in-law AJ Prime — even though it was against strict protocol which allowed only hongi, handshakes and curtsies. Prince Harry didn't hesitate, however.
Prime worried her name would be scrubbed from the Governor-General's list of future events, until she saw the royal high-five was included in the event's official video.