Prince William's heartbreaking realisation when he was just a child on early visit with Princess Diana

Prince William has opened up about a profound childhood experience that still impacts him today in a new heartfelt documentary.

Since 2019, the Duke of Cambridge has been the patron of The Passage, a homeless charity with a personal significance as it was a cause close to his mother's heart. It was also the first charitable institution he visited with Princess Diana back in 1993.

In the revealing two-part series "Prince William: We Can End Homelessness," he reminisces about being taken to The Passage as a young boy. He shared: "My mother took me to The Passage; she took Harry and I both there. I must have been 11 at the time, maybe 10. I had never been to anything like that before, and I was a bit anxious about what to expect.

"I remember having some good conversations, playing chess, chatting and that's when it dawned on me that there were other people out there who don't have the same life as you do. You know, when you're quite small, you just think life is what you see in front of you and you don't really have concept to look elsewhere."

William continues by explaining the moment of realisation, saying, "It's when you meet people, as I did then, who put a different perspective in your head and say, 'Well, I was living on the street last night,' and you're like, 'Woah.' I remember that happening."

William reminisced about his mother's innate ability to make people feel comfortable, saying: "My mother went about her usual, making everyone feel relaxed, having a laugh and joking with everyone," he said. "I remember at the time kind of thinking, 'Well, if everyone doesn't have a home, they're all going to be really sad.' But it was incredible how happy an environment it was.", reports the Mirror.

The Passage has been providing essential support and services since 1980 to transform the lives of those without homes. William, who first visited with his mother, has shown ongoing commitment to the charity, including spending a night on the streets in 2009 to understand the hardships faced by the homeless.

The cause is deeply important to William, influenced by his late mother Princess Diana, who instilled in him an appreciation for his privileged life within the palace walls. He continues to share this awareness with his children, Prince George, Princess Charlotte, and Prince Louis.

"I am starting to introduce homelessness to my children on the school run. The first few times I thought, 'Do I bring this up or should I wait to see if anybody noticed? ' Sure enough they did and they were just sort-of silent," he shared. "After I said what was going on, I could see their brains try to work out what that means. I do think it's really important that we start those conversations when the children are small so they're not just living, you know, in their own little worlds."