Prince William recalled a transformative childhood moment he shared with his brother Prince Harry in his two-part documentary Prince William: We Can End Homelessness.

In a clip broadcast on Saturday, the royal said his interest in the charity began after his late mother, Princess Diana, took him and his brother to The Passage, a UK charity that supports those experiencing or at risk of homelessness.

“My mother took me to the Passage; he took both harry and me there. He must have been 11 at the time, maybe 10,” William said. “I had never been to anything like this before and was a little worried about what to expect.”

“Mum usually managed, making everyone feel relaxed, laughing and joking with everyone. I remember thinking at the time, “Well, if everyone doesn’t have a house, everyone will be really sad.” But it was incredible what a happy medium it was,” he recalled.

“I remember having some good conversations, playing chess, chatting, and then I realized that there are other people who don’t have the same life as you.”

William continued, “You know, when you’re young enough, you think life is what you see in front of you and you have no idea where to look. It’s when you meet people, like I did then, who put a different perspective in your head and say, “Well, I lived on the street last night,” and you’re like, “Woah.” I remember it happening.”

The documentary is believed to be the first time the royal has spoken publicly about his brother amid their family rift.

Reports emerged that the split between the Duke of Sussex and his brother was “very bad” but not “irreparable” over the summer, when their relationship appeared to hit another snag when Harry requested extra security for himself and his family while visiting his home country.

Around the same time, sources also reported that King Charles stopped talking to Harry despite the son’s attempts to check on the monarch’s health after him cancer diagnosis.

A royal insider previously told Page Six that the only way for Harry and Charles to reconcile would be for the monarch to give Harry enhanced security clearance ask for several years.

“As monarch, he is the most important decision-maker. That’s how father and son could reconcile,” the source said.

“Prince William: We Can End Homelessness” will be broadcast on October 30 and 31 on ITV in the UK.