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Prince William and Prince Harry have always been determined to keep their mother’s legacy alive.

On Thursday, the Duke of Cambridge and the Duke of Sussex will reunite to unveil a statue of their mother, Princess Diana, on what would have been her 60th birthday. The event in the Sunken Garden at London’s Kensington Palace will be their second public meeting since Harry, 36, and his wife Meghan Markle stepped away from royal duties over a year ago.

"Prince William and Prince Harry have wanted to do something for Diana for such a long time," True Royalty TV co-founder Nick Bullen told Fox News. "There have been various attempts. The Diana Memorial fountain was something that didn’t really capture the essence of Diana, many believed. But this statue I’m told is an amazing piece of work and a fitting tribute."

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Princess Diana passed away in 1997 from injuries she sustained in a Paris car crash. She was 36.

Princess Diana passed away in 1997 from injuries she sustained in a Paris car crash. She was 36. (Photo by Tim Graham Photo Library via Getty Images)

"It’s strange, isn’t it?" the filmmaker continued. "Here we are, nearly 24 years after her death. And there has been no real permanent memorial to one of the most famous women in the world. I think it’s about time. I believe this is absolutely fitting. But it took time. There were lots of concerns about how to capture her image in stone because she was so beautiful. And there were lots of conversations about the memorial and how it would capture the essence. And the boys were very hands-on in the planning process."

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Britain's Prince Harry (L) and older brother Prince William will unveil a statue honoring their late mother Princess Diana.

Britain's Prince Harry (L) and older brother Prince William will unveil a statue honoring their late mother Princess Diana. (TOLGA AKMEN/AFP via Getty Images)

Bullen an award-winning documentarian, has been making programs about the royal family for nearly 20 years and has worked closely with their father, Prince Charles, for eight. In time for the statue unveiling, the streaming platform will be celebrating Diana’s birthday with a collection of documentaries, including two U.S. premieres: "Diana: A Mother’s Love" and "Diana at 60."

Bullen said there’s no denying Diana’s lasting imprint on the monarchy.

"The Princess of Wales changed so much of the British monarchy," he explained. "She had an impact almost from the very first day she appeared in the papers… She came from a different generation. She was a young woman who gave the monarchy a very modern look."

"She reached out to AIDS patients and touched people with HIV when no one else was touching them," he shared. "She embraced what is considered ‘unglamorous’ causes, like homelessness and landmines.  She touched so many people because she got down to their level. She held babies on her lap. She interacted with the public in a way that perhaps royalty hadn’t done before. It’s a very different way of being royal."

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In time for what would have been Princess Diana's 60th birthday, True Royalty TV is releasing a collection of documentaries celebrating the life and legacy of the late royal.

In time for what would have been Princess Diana's 60th birthday, True Royalty TV is releasing a collection of documentaries celebrating the life and legacy of the late royal. (Photo by Julian Parker/UK Press via Getty Images)

Bullen said that the documentary, "Diana: A Mother’s Love," explores how the princess made her mark as a doting parent who openly embraced her sons and was determined to give them as normal of a life as possible.

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Princess Diana was described by those who knew her as a doting mother who wasn't afraid to embrace her children publicly despite her royal status.

Princess Diana was described by those who knew her as a doting mother who wasn't afraid to embrace her children publicly despite her royal status. (Photo by Antony Jones/Julian Parker/UK Press via Getty Images)

"She was very hands-on as a mother," said Bullen. "She insisted on the babies being on tour with her in the early years. Look at Harry and William now. They’ve taken their children with them on tour. This had never been done before. But Diana changed everything. And she wanted her sons to have a very normal life. You saw them in theme parks, you saw them on beach holidays. These were not things that we’d seen royals do before. Both of the boys have embraced that approach as parents."

Bullen pointed out that William, who is second in line to the throne, was drawn to his wife Kate Middleton because she came from a more normal upbringing. The couple met at the University of St. Andrews and tied the knot in 2011.

"Diana was fully aware of the duty and destiny her sons had, but she wanted them to feel as normal as possible," said Bullen. "You can especially see that in William. He is a working dad married to a working mom. They live in a palace, but they live a relatively normal upper-class British life. And I think that’s very much in tune with Diana and how she raised her sons."

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FILE PHOTO OF 6SEPT95 - The Prince and Princess of Wales, Prince Harry, and housemaster Dr Andrew Gayley (behind) escort Prince William (2R), second in line to the throne, for his first day of term at the world famous Eton College September 6, 1995. Princess Diana and her millionaire companion Dodi Al Fayed were killed in a car crash August 31 in Paris after being chased by photographers on motorcycles.DIANA - RP1DRIDWOXAA

Princess Diana with sons Prince Harry and Prince William alongside Prince Charles. They were accompanied by housemaster Dr. Andrew Gayley (behind) in 1995. (Reuters)

Bullen said he hopes fans of Diana’s will get a chance to explore the new documentaries, which show a completely different side to a beloved royal – one that continues to influence her sons today.

"Before all this bickering and mudslinging between all the various royal households, these take you back to a more innocent age in many ways," he said. "We can see how glorious this beautiful princess was with her boys. I think we need programs that uplift and these do in a lot of different ways."

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Both Prince William and Prince Harry have honored Princess Diana with their daughters' middle names. 

Both Prince William and Prince Harry have honored Princess Diana with their daughters' middle names.  (Jayne Fincher/Princess Diana Archive/Getty Image)

On July 29, 1981, Lady Diana Spencer married Prince Charles, the heir to the British throne, when she was 20 years old. They welcomed William in 1982, followed by Harry in 1984. The couple divorced in 1996. Diana passed away in 1997 from injuries she sustained in a Paris car crash. She was 36.

The Associated Press contributed to this report.