Princess Diana is featured in a framed photo given to Prince Harry

Diana, Princess of Wales was definitely on her son Prince Harry's mind as he followed in her footsteps with a visit to Mildmay, a London hospital dedicated to HIV patients. The engagement was special as the late princess was a regular visitor of the charity.

Harry was marking the organization's 150th anniversary and the opening of the hospital's newest facilities. He saw how the focus of its work has changed significantly in the past two decades from end-of-life care to rehabilitation, thanks to medical advances.

Arriving at the hospital in a smart suit and bright-blue tie, Harry was greeted by a chorus of well-wishers who waved Mildmay flags and youngsters from the nearby Virginia Primary School, who had drawn Harry a special welcome banner.

TAP TO VIEW GALLERYPrince Harry was given framed photographs of his late mother Princess Diana, who would visit Mildmay hospital.

When the Prince, 31, asked the schoolchildren what lessons they were missing and they replied, the cheeky royal said, "Maths? Boring! Oops, I didn't say that."

At the start of the visit, Harry signed the guest book in the Diana, Princess of Wales meeting room. He looked visibly moved when he was presented with a handmade Christmas card and framed photographs of his mom visiting the hospital.

The prince was marking the opening of the hospital's new facilities.

Harry was then given a tour of the facility, which is now Europe's only centre dedicated to treatment, rehabilitation and medical care for people with complex HIV-related health conditions. The prince also met staff and patients and learned about the dangers of late diagnosis.

The culmination of the visit came in the form of a cake cutting, when Harry was given the honour of digging into the Mildmay's birthday cake.

Harry also celebrated Mildmay's 150th anniversary.

The engagement will have struck a chord with Harry, who was no doubt reminded of his mother. The People's Princess made about 17 visits to Mildmay, three of which were official. It was during one of these visits that Diana kissed a patient on the cheek, a powerful gesture that helped to break down the stigma that surrounded HIV at the time.

The princess would also visit the hospital in her private time and often spend time with patients who were nearing the end of their life. Several had been abandoned by their families and Diana's care and compassion offered them great comfort.

Princess Diana visited Mildmay about 17 times.

It seems Harry is keen to champion his mother's cause as he has continued to show support for HIV victims.

The prince has just come back from a trip to Lesotho and South Africa where he promoted the work of his charity Sentebale, which works with those affected by HIV. Many of the children supported by the charity – which means Forget Me Not in Sesotho – have lost their parents.

Harry is also keen to help tackle the stigma in a wider context outside of Lesotho. Overall, the number of people living with HIV in the U.K continues to increase, and the number of those living with undiagnosed HIV remains high.

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