If you were unaware, the brothers have been at odds for years and reportedly did not interact the last time that they were seen at the same public event.
The 42-year-old Prince of Wales referenced his brother in a clip from his forthcoming documentary Prince William: We Can End Homelessness. It appears to be the first time that he's spoken publicly about the Duke of Sussex in years.
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In the clip from the ITV documentary, the Prince recalls attending a charity called The Passage with his mother Princess Diana and brother.
"My mother took me to The Passage; she took Harry and I both there. I must have been about 11, I think, at the time. Maybe 10. I had never been to anything like that before, and I was a bit anxious as to what to expect," he recalled.
Prince William continued, noting, "My mother went about her usual cause of making everyone feel relaxed and having a laugh and joking with everyone. I remember at the time kind of thinking, 'Well, if everyone has not got a home, they're all going to be really sad.' But it was incredible how happy an environment it was."
"I remember having some good conversations, to playing chess and chatting. 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 don't really... You just think life is what you see in front of you and you don't really have concept to look elsewhere. 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," he said.
Prince William: We Can End Homelessness premieres on ITV1 and ITVX on October 30 and 31 at 9pm. You can watch the clip below.