Princess Diana died Aug. 31, 1997, at the age of 36. It has been 21 years since the infamous car crash killed Princess Diana, and her two surviving kids, Princes William and Harry, continue to grief the loss of their mother.

On various occasions like the reception for the Child Bereavement Charity in March 2009, both of them have opened up about the experience of dealing with their mother’s death at a young age. William was 15 and Harry was 12 when the “People’s Princess” met with her untimely demise.

Here are a few quotes by William and Harry about the pain of losing Princess Diana, courtesy PopSugar

Prince William:

"Time makes it easier. I still miss my mother every day — and it's 20 years after she died."

“Initially, there is a sense of profound shock and disbelief that this could ever happen to you. Real grief often does not hit home until much later. For many it is a grief never entirely lost. Life is altered as you know it, and not a day goes past without you thinking about the one you have lost. I know that over time it is possible to learn to live with what has happened and, with the passing of years, to retain or rediscover cherished memories."

"Losing a close family member is one of the hardest experiences that anyone can ever endure. Never being able to say the word 'Mummy' again in your life sounds like a small thing. I too have felt —and still feel—the emptiness on such a day as Mother's Day."

Princess Diana's Funeral Prince William (left) and Prince Harry, the sons of Diana, Princess of Wales, bow their heads as their mother's coffin is taken out of Westminster Abbey following her funeral service, London, England, Sept. 6, 1997. Photo: Getty Images/ Adam Butler

"I still find it difficult now because at the time it was so raw. And also it is not like most people's grief, because everyone else knows about it, everyone knows the story, everyone knows her. It is a different situation for most people who lose someone they love, it can be hidden away or they can choose if they want to share their story."

"The very last memory I have is a phone call from Balmoral [Castle in Scotland]. At the time, Harry and I were running around, minding our own business, playing with our cousins and having a very good time. Harry and I were in a desperate rush to say 'Goodbye, see you later, can I go off?' If I'd known what was going to happen I wouldn't have been quite so blasé about it. That phone call sticks in my mind quite heavily."

Prince Harry:

"I never really dealt with what had actually happened. So there was a lot of buried emotion, and I still didn't even want to think about it."

"I really regret not talking about it. It is OK to suffer, but as long as you talk about it. It is not a weakness. Weakness is having a problem and not recognizing it and not solving that problem."

"Losing your mother at such a young age does end up shaping your life massively, of course it does. And now I find myself trying to be there and give advice to other people who are in similar positions."

"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. I don't think any child should be asked to do that, under any circumstances. I don't think it would happen today."

"I hope she's looking down [at our family] with tears in her eyes being incredibly proud of what we've established. I'm sure she's longing for me to have kids so she can be a grandmother again . . . but I hope that everything we do privately and officially, that it makes her proud."