He recently teamed up with his late mother's dear friend Sir Elton John for the fight to de-stigmatise the disease.
On Wednesday, at the Elton John AIDS Foundation's 15th annual An Enduring Vision benefit gala in New York City, the music legend opened up to HELLO! about having the Princess of Wales' son champion his cause and how the ginger-haired royal takes after mum Diana.
"[Princess Diana] had that ability to walk into a room and make people feel very at ease and he does that, too," said Elton
"People love him because he has his mother's ability to communicate so brilliantly on a very, very humble level and that's what she had," the 69-year-old told HELLO! at the gala, sponsored by Clase Azul Tequila and Chopin Vodka.
The Candle in the Wind singer continued: "[Princess Diana] had that ability to walk into a room and make people feel very at ease and he does that, too."
Over the summer, Harry and Elton joined forces in South Africa for the 21st International AIDS Conference. Discussing the royal's participation with his work, the dad-of-two said: "It's great because you know he appeals to young people."
The singer with his husband David Furnish
"I'm a little old so I can't get through to the people that he can get to," David Furnish's husband added. "We need more people like that to get through to young people because infections among young people are growing, not falling. So we need people like him."
Apart from his work with HIV/AIDS and veterans, the royal has been keeping busy with his new relationship with American actress Meghan Markle.
As for whether Elton will get tapped to perform at a possible future royal wedding, husband David laughed: "I don't know anything about that."