The royals will attend a private service to rededicate the grave of Diana at Althorp House on Saturday, July 1, which would have been the Princess of Wales' 56th birthday. The service will be conducted by The Archbishop of Canterbury, and will be attended by her family.
The Princess of Wales died on Aug. 31, 1997 in a car crash in Paris, France, when William was 15 and Harry was 12. Harry recently opened up about being forced to walk behind the casket of his late mother during her highly publicized funeral.
"My mother had just died, and I had to walk a long way behind her coffin, surrounded by thousands of people watching me while millions more did on television," he told Newsweek. "I don't think any child should be asked to do that, under any circumstances. I don't think it would happen today."
"I intuitively know what my mother would like me to do and want to progress with work she couldn't complete," he said of Diana, an outspoken HIV/AIDS activist. "My mother died when I was very young. I didn't want to be in the position I was in, but I eventually pulled my head out of the sand, started listening to people and decided to use my role for good."