The childhood visits with his mom "left a deep and lasting impression on me," William said at the charity

By Simon Perry
Updated May 13, 2016 12:40 PM
Source: Kensington Palace/Twitter

Prince William spent Friday afternoon returning to a homeless center that he first visited with his mother Princess Diana more than two decades years ago.

William, who has made homelessness one of the main focuses of his public work, said the childhood visits “left a deep and lasting impression upon me.”

Speaking at The Passage in London, where he officially opened the charity’s refurbished St. Vincent’s Centre, William met a woman who remembered him from those early visits.

Volunteer Iris Moore, 87, who was there when young William visited for a second time with Diana and his brother Prince Harry in 1994, asked him, “Do you remember me?”

He admitted that he didn’t but said he remembered the visit, when he and his brother played cards with the homeless.

“You’ve grown,” said Moore.

“When he was a child he came with Harry – Princess Diana brought him,” recalled the former nurse. “She wanted him to see how the other half lives. It was a nice afternoon. She sat with all the homeless and the two boys. They were a little bit shy.

“To see him again as a grown man was very special. But I thought he looked very young.”

In a further reminder of that visit, he was presented with a photograph of the occasion, showing Diana, Harry and himself with one of the homeless men.

Mark Smith, 45, a homeless ambassador who presented him with the picture, told reporters, “He remembered the t-shirts they had on. It was just so touching. He laughed – he found it quite strange that we still had a photograph of him as a child with his mum.”

William, who is patron of charity homeless campaigning charity Centrepoint (with which he spent a night sleeping on the streets in 2009), first visited the Passage in December 1993 with his mother and then returned with her and Harry the next year.

The organization runs the U.K.’s largest resource center for homeless and insecurely housed people, a number of homelessness prevention projects and two innovative accommodation services.

Related Video: 15 Times Princess Kate Channeled Princess Diana

William and Harry have been gradually building up the work that carries on what their mother started, in areas from homelessness to helping vulnerable children with HIV.

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In his exclusive interview with PEOPLE earlier this month, Harry said that both of them were trying to fill the “void” left by Diana.

“When she died there was a gaping hole, not just for us, but for a huge amount of people across the world. If I can try and fill a small part of that, then job done! I will spend the rest of my life trying to fill that void as much as possible. And so will William.”