Welsh rugby star Gareth Thomas has told the Duke of Sussex his success on the pitch will fade in years to come but his lasting legacy will be raising awareness about HIV.
Thomas and Harry, a long-term HIV campaigner, spoke about the impact the sportsman has had since revealing his HIV status in a film released by the Terrence Higgins Trust to mark World Aids Day - December 1.
The ex-fullback, who captained both Wales and the British Lions, was the highest-profile sportsman in the UK to reveal he was gay when he came out in 2009, and in September he said he was forced to reveal he was HIV positive after a tabloid newspaper threatened to publish the personal information.
In the video, filmed a few weeks ago in the stands at the Twickenham Stoop - home of Premiership Rugby club Harlequins - Harry joked about the Welshman's "big" trophy cabinet.
Thomas replied, laughing: "Yeah, it's big. But I look at it and think, do you know what, they'll gather dust and they'll go away and be forgotten about, but I'd like to think where we're going on this journey of education and breaking stigma around HIV is something that will have a legacy everlasting."
Harry praised Thomas's impact on raising HIV awareness since he revealed his status, saying: "We know there's a hell of a lot to do, but what you've managed to do in just the space of six or eight weeks has been transformational - genuinely transformational.
"As you said, we should all know our status and if it is treated just the same as any other virus then that is exactly what should be happening.
"From my perspective, all I can do is thank you for the difference that you've made, the lives that you're saving on a daily basis now and you'll have every single one of us backing you the whole way. You're not in this alone."
The Terrence Higgins Trust announced in November the former rugby player would be a member of its new HIV Commission, established with the National Aids Trust.
The sports star told the duke the panel's "common goal" was "in 10 years' time within England, there will be zero new transmissions of HIV".
Thomas also said he had once thought his purpose in life was to "play rugby and to represent Wales" but he now felt his sporting career had given him the "platform" to change other people's lives.
The Terrence Higgins Trust has released research showing almost three out of four British adults (74%) are aware the Welshman has spoken publicly about living with HIV.
The organisation commissioned a YouGov poll of 2,143 British adults which also found that of those aware of Thomas's HIV status, 11% said it had improved their overall knowledge of HIV, while 7% said it improved how they would treat someone living with the virus.
Thomas's announcement in September also led to a surge in orders to the charity for HIV tests, increased website hits and calls to its helpline.
But the survey found longstanding views about HIV remained, with 39% of people questioned saying they would feel uncomfortable kissing someone with the virus, while 29% would feel uncomfortable going on a date with someone who had HIV.
The charity said there is no risk of HIV being passed on through kissing or other day-to-day contact.