Prince William has opened up about his late mother Princess Diana and how she inspired him to become a dedicated activist for those less fortunate while pledging to continue his efforts towards helping those in need.

In a personal essay he wrote for The Big Issue magazine, the Prince spoke about his support and appreciation for the magazine and everything it does to help issues of homelessness and poverty, revealing it was his mother who first inspired his desire to create change.

“I was 11 when I first visited a homeless shelter with my mother, who in her own inimitable style was determined to shine a light on an overlooked, misunderstood problem,” William revealed.

The Prince attributed his 40th birthday to being a time in his life where he plans to engage in further efforts to help those who are struggling.

“And while I may seem like one of the most unlikely advocates for this cause, I have always believed in using my platform to help tell those stories and to bring attention and action to those who are struggling. I plan to do that now I’m turning 40, even more than I have in the past,” he said.

“So, for my part, I commit to continue doing what I can to shine a spotlight on this solvable issue not just today, but in the months and years to come.”

The candid admission comes as the beloved Prince celebrates his milestone 40th today, June 21, less than two weeks after he was spotted selling The Big Issue magazine on the streets of Westminster in London.

William went on to speak about his unconventional day out while paying tribute to the volunteer vendors that dedicate their everyday lives to selling the street magazine which allows them to earn a living.

“I wanted to experience the other side and see what it was like to be a Big Issue vendor. My time was truly eye opening. I was lucky to join Dave [one of the vendors] on a warm, sunny day in June,” William said.

“People recognised a familiar face and were happy to give me the time of day. But that isn’t the case for the vast majority of Big Issue vendors, who sell year-round, including through the bleak winter months and are barely given a second glance by passers-by.”

Prince William spent his day alongside volunteer Big Issue vendor David Martin, 60, who the Prince praised for his undeniable dedication to the cause and for setting an example for the community.

“A hard working, funny, joyful man, Dave is the kind of person we should all be actively encouraging and supporting,” William said.

“Instead, people often just ignore him. And while The Big Issue provides mechanism by which Dave can provide for himself, earn a living and in his words, regain some self-respect, it is reliant on us playing our part too.

“Because he can only succeed if we recognise him, we see him and we support him.”

The Prince acknowledged his privilege of being able to be a part of something bigger.

“I count myself extremely lucky to have a role that allows me to meet people from all walks of life, and to understand their full story – whatever it may be. It’s a privilege that many of us, busy with our days, don’t always afford,” he said.

William ended the article as he revealed his plans to include his children in his “inspiring” efforts, just as Diana had included him.

“And in the years ahead, I hope to bring George, Charlotte and Louis to see the fantastic organisations doing inspiring work to support those most in need – just as my mother did for me,” he said.

“As she instinctively knew, and as I continue to try and highlight, the first step to fixing a problem is for everyone to see it for what it truly is.”