Prince Harry honours Princess Diana and his nanny at a new charity centre

Prince Harry has ensured that Princess Diana's memory will live on in his charity work, naming rooms in Sentebale's new flagship centre after his late mother and beloved nanny, Olga Powell, who cared for Harry and Prince William for 15 years. A striking dining hall with sweeping views over the imposing sacred Thaba Bosiu plateau – believed to be the birth place of Lesotho as a nation – is named the Diana, Princess of Wales Hall.

TAP HERE FOR MORE PHOTOS

The new centre will help children affected by HIV/AIDS.

Olga took charge of the young princes throughout the period of their parents' turbulent marriage breakdown and remained close to them until her death in in September 2012 at 82.

Olga, who was a guest of honour at William’s wedding to then-Kate Middleton in April 2011, is also remembered in a touching plaque outside a room at the new Mamohato Children's Centre. It reads: "The Welcome Centre: In loving memory of Olga Powell."

The dining room has been named the Diana, Princess of Wales Hall.

Harry will offically open the 96-bed centre, which will host camps for children struggling to overcome their HIV/Aids diagnosis.

He will inspect poignant finishing touches, including the named rooms and a colourful "Giving Tree" inscribed with the names of supporters of the project. They include Sir Elton John and his husband, David Furnish, and their sons, Zachary and Elijah, and close friends Harry Tom Inskip and Adam Bidwell.

TAP HERE TO SEE THE FULL GALLERY

A plaque honouring William and Harry's late nanny hangs in the centre.

Harry decided to act after visiting the tiny landlocked nation during his gap year in 2004. After discussing the plight of the country's children with Prince Seeiso of Lesotho, the two royals joined forces to launch Sentebale – which means Forget-Me-Not in the local Basotho language – in memory of their mothers.

Princes William and Harry with their nanny, Olga Powell.

The charity was founded in 2006 and fundraising began for the Mamohato Centre, named after Prince Seeiso’s late mother Queen Mamohato, in 2013. Building work on Sentebale’s first purpose-built children’s camp started in April 2014 and was completed in August this year.

Harry has already visited the site three times, but this will be his first opportunity to see the finished product.

Speaking ahead of the official opening ceremony, Prince Seeiso told Hello!: "If you were to look at our history in terms of what Sentebale is, it’s in honour of our late mums.

TAP FOR MORE PHOTOS FROM LESOTHO

The plaque honouring Princess Diana.

"Mamohato, who has in Lesotho played a very important role in terms of child care and orphan care, and Princess Diana, who really broke ground in terms of breaking out of what had been done before she came on the scene."

Praising Harry's approach to helping the children of Lesotho, he added, "He came from a similar background from his mom – you need to be seen and to feel what other people are feeling so that you can make a difference in your own way."

Sentebale CEO Cathy Ferrier said the prince was keen to honour both his mother and former nanny.

The Thaba Bosiu plateau where the centre is located.

"Sentebale was started in memory of both their mothers," she said. "The centre is named after Seeiso's mother but we felt it was right to acknowledge Harry's mother as well so we decided that the dining hall was the appropriate place, it's the place where all the children will gather three times a day and do plays and drama as well so it felt like the right kind of place."

She said mourners at Olga’s funeral had donated money to Sentebale at Olga's request. "She knew Harry cares hugely about it and so she cared about it, too.

"In one of the planning meetings I was having with Harry we said what shall we do about naming and we decided the welcome centre should be in memory of Olga.

"This building is so much Harry's building; he designed the front bit. This was his drawing that we sent to the architect."

Lesotho, the tiny, mountainous “Kingdom of the Sky,” has the second highest rate of HIV infection in the world. The disease has wiped out a generation of young adults, meaning there are no longer enough to care for the children. Some 21,000 young people aged between 10 and 19 have been diagnosed HIV positive, and a third of children have been left orphaned.

The stigma surrounding the illness has prevented many youngsters from seeking treatment or going to school. But Sentebale plans to reverse the situation by bringing them to camps to learn about the importance of taking their medication and getting an education and hopes to expand the camps to other parts of Lesotho.