Prince Harry on How Mom Princess Diana Inspired Invictus Games: 'I Felt the Lift She Got from Helping Others'

Prince Harry learned the power of helping others from his mother, Princess Diana.

Ahead of the 2016 Invictus Games in Orlando, Prince Harry told PEOPLE that he hoped to make his mother proud. Six years later at the fifth Invictus Games — and now as a husband to Meghan Markle as well as a father to son Archie and daughter Lilibet — he believes he has.

"I certainly hope and believe everything I do makes her proud," the Duke of Sussex tells PEOPLE in this week's exclusive cover story. "In the 12 short years I was lucky enough to have with her, I saw and felt the energy and lift she got from helping others, no matter their background, ailment or status. Her life and theirs was better for it, however short theirs or hers was."

He adds, "I honor my mother in everything I do. I am my mother's son."

In an interview with Today's Hoda Kotb that aired Wednesday, Prince Harry said he felt Princess Diana's presence was "constant," adding, "It has been over the last two years. More so than ever before."

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Harry also said that he tells his kids about "Grandma Diana" and has photos of her around their home in California, where the family relocated in 2020.

Prince Harry, 37, has carried on the work for causes that were important to Diana, who died in 1997 at age 36. In addition to working with organizations to call for an international ban on landmines, even walking in the footsteps of Diana in a former warzone in Angola, he has continued to advocate for HIV awareness.

"What my mom did, and what so many other people did at that time, was to smash that wall down. To kick the door open and say, 'No. When people are suffering, then we need to learn more, and if there's a stigma that's playing such a large part of it, then what we really need to do is talk about it more,' " Harry said in a conversation with rugby player Gareth Thomas, creator of the Tackle HIV campaign. "That kind of made people feel a little bit uncomfortable to start with. But stigma thrives on silence. We know that."

In July, Prince Harry teamed up with his brother, Prince William, to unveil a statue honoring their late mother at Kensington Palace on what would have been her 60th birthday.

Prince William and Prince Harry formed a committee that included one of Diana's sisters, some friends, experts and charity contacts to help come up with a fitting tribute to the late princess. They commissioned Ian Rank-Broadley, the sculptor behind the image of their grandmother Queen Elizabeth that has been used to decorate all British coins since 1998, as the person to create the tribute.

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"In the past quarter of a century, they have placed their mother right at the heart of the royal family," historian Robert Lacey, author of the bestseller Battle of Brothers: William & Harry: The Inside Story of a Family in Tumult, told PEOPLE.

At the ceremony, the brothers decided to forego individual speeches and instead issued a joint statement that maintained focus on their mother: "Today, on what would have been our mother's 60th birthday, we remember her love, strength and character, qualities that made her a force for good around the world, changing countless lives for the better," William and Harry said.

They added, "Every day we wish she were still with us."