Prince Harry says his late mother felt a "responsibility" to "shine her spotlight" on issues being ignored.
The 33-year-old royal collected the Legacy Award at the Attitude Awards, which took place at London's Roundhouse on Thursday (12.10.17), on behalf of Princess Diana - who tragically passed away in 1997 aged 36 years old - and on picking up the accolade, that posthumously recognises Diana's charity work, Harry spoke out about the inspiration behind his parent's projects.
Speaking at the star-studded bash, the red head said: "She felt a responsibility to shine her spotlight on the people and issues that were often ignored. She knew that AIDS was one of the things that many wanted to ignore and seemed like a hopeless challenge."
Diana - who set up the UK's first HIV/Aids unit at London Middlesex Hospital in 1987 - "knew exactly" what she was doing when she met with a man who had HIV and took off her gloves to greet him.
Harry continued: "She knew that the misunderstanding of this relatively new disease was creating a dangerous situation when mixed with homophobia.
"So, when, that April [in 1987], she took the hand of a 32-year-old man with HIV, in front of the cameras, she knew exactly what she was doing."
And Harry has admitted he and his older brother the Duke of Cambridge, 35, are "incredibly proud" of their mother's achievements.
Harry added: "[We are] incredibly proud of what our mother achieved.
"I believe that she would be telling everyone across society - not just those most at risk - that with effective treatment being free and available in the UK, that we must all embrace regular testing - both for our own sake and for those that we love."
And once Harry received the award the publication revealed one of its limited edition magazine covers, which features Diana on the front.