He lost his mom, Princess Diana, at age 12, but now Prince Harry is opening up about her profound influence.
"All I want to do is make my mother incredibly proud," he tells PEOPLE in an exclusive interview in this week's cover story. "That's all I've ever wanted to do."
Speaking in the Audience Room of Kensington Palace just before he set off for his Invictus Games in Orlando – on Wednesday he'll make a stop in Palm Beach, Fla., for a charity polo match – the royal, 31, reflected on the ways in which his late mom continues to inspire him.
"When she died, there was a gaping hole, not just for us but also for a huge amount of people across the world," he says. "If I can try and fill a very small part of that, then job done. I will have to, in a good way, spend the rest of my life trying to fill that void as much as possible. And so will William."
To read the full interview with Prince Harry, pick up the latest issue of PEOPLE, on newsstands Friday
In the wide-ranging interview heading into the second Invictus Games – more than 500 athletes are expected to compete from around the world May 8-12 – Prince Harry also spoke about his own military experience, his thoughts on fatherhood (yes, he wants kids, but there's "no rush!") and his memories of visiting Disney World as a kid with his mom and older brother.
He says he doesn't consciously model himself on how his mother carried out her charitable work.
"I enjoy what I do. But I don't do things because I feel as though my mother would want me to do them."
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And yet, he says, "I know I've got a lot of my mother in me. I am doing a lot of things that she would probably do."
Harry also spoke about how his own military experience spurred him to create Invictus as a way of supporting his fellow service members.
Despite being well trained and flying a multi-million dollar Apache helicopter during his second tour of Afghanistan in 2012-13, the former British Army captain talks about how powerless he felt as he flew missions to save lives.
"You turn up and you think you're invincible in a super-duper aircraft, but you're helpless," he says. "Then I come back and I say, 'How can I use my name and that spotlight to the best effect?' " Creating the Games, he notes, was "almost like a cure for that pain I had back then."
Tickets for the Orlando Games can be purchased here.