In an interview with the Telegraph's Bryony Gordon published at Easter, the Prince revealed that he had sought counselling in his late twenties after struggling to come to terms with the death of his mother, Princess Diana, in 1997.
The story was immediately picked up across the media. The prince was praised for his frankness. Charities reported a rise in people making enquiries. The country – and the world – was talking about mental health, with further social content also earning coverage and clicks.
This was far from a one-off flight of candour – the interview came about as a result of Gordon’s interest in Heads Together, the mental health campaign launched in May last year by the Royal Foundation, the charity led by the prince, his brother, and the Duchess of Cambridge. As Harry met Gordon and others and talked about mental health, he realised that he needed to talk about the challenges he had faced.
It was decided Gordon was the right person to do that with. The princes’ comms secretary Jason Knauf told PRWeek: "Bryony Gordon has been a tireless campaigner for mental health and her interest is personal and authentic. She approaches a difficult subject with warmth and lots of humour – that made her podcast a perfect place to have a conversation that Prince Harry wanted to be fun and optimistic.
"We're delighted that it has kicked off a national conversation on mental health."
It was arranged that the interview would be published a week before the London Marathon, where Heads Together was the official charity partner, with all the associated publicity that entails. It was the first time the marathon's charity of the year was an organisation solely focused on mental health.
This year, marathon sponsor Virgin Money paid for each competitor to receive a Heads Together headband in their race pack, adding to the charity's branding around the event. Heads Together was handed 250 places in the marathon for fundraising runners and another 450 opted to back the cause having got a place elsewhere - with Gordon herself one of these.
Got a bit teary writing this. It's a tribute to the UK, & anyone who's ever admitted to a mental health issue https://t.co/xbetrhnt8W— Bryony Gordon (@bryony_gordon) April 22, 2017
An emotive BBC documentary Mind Over Marathon, following the fortunes of marathon hopefuls with a variety of mental health challenges, aired in two parts either side of race day, keeping up the conversation.
All in all it was a triumph for the prince - and indeed for comms man Knauf, who has more than once been criticised in the press for his handling of the royals since he joined from RBS two years ago.