Despite their ongoing tensions, Prince William recalled a pivotal memory he shared with his brother, Prince Harry, from their childhood recently in a new documentary about homelessness.
"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," the Prince of Wales said in a preview clip of his new ITV documentary called "Prince William: We Can End Homelessness."
A photo in the documentary showed the two boys dressed casually at the homeless charity, smiling for the camera as Harry sits on his mother, Princess Diana’s lap.
William said Princess Diana made everyone there "feel relaxed and having a laugh and joking with everyone" in her usual way when they arrived at the center.
"I remember at the time kind of thinking, ‘Well, whoever’s not got a home, they’re all going to be really sad,’ but it was incredible how happy an environment it was," he added in the clip.
Despite an official 40th birthday wish from the Kensington Palace X account, William and Harry have had a strained relationship since the Duke of Sussex’s marriage to Meghan Markle, and William's remarks in the documentary are believed to be his first public mention of his brother in years.
It was strained further after Harry and Meghan left England in 2020 for California.
He and Meghan did a tell-all sit down with Oprah Winfrey in 2021 from California in which they leveled racism allegations at an unnamed member of the royal family and hit out at the institution in the Netflix docuseries "Harry & Meghan" in 2022.
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Last year, he published the memoir "Spare," in which, among other allegations, he accused William of physically attacking him in an argument over Meghan at his London home in 2019, after he and Meghan were married.
Most recently, William and Harry also appeared to avoid each other at the memorial service for their mother’s brother-in-law, Lord Robert Fellowes, in August.
PRINCE WILLIAM DOESN'T WANT PRINCE HARRY AT CORONATION BUT WON'T MAKE 'FOOLISH' MISTAKE: EXPERT
The brothers "were keeping their distance" at the memorial, the Sun reported.
In June, Harry turned down an invitation to Hugh Grosvenor, the Duke of Westminster’s wedding in northern England because William was attending, a royal expert told Fox News Digital at the time.
"Even if Harry showed up and slunk into the back row, there would be enough press coverage and general hysteria over the two brothers being in the same room to overshadow the wedding entirely," Christopher Andersen, author of "The King," explained.
Harry flew back to London for a short visit with his father in February after King Charles’ cancer diagnosis, but didn’t meet with William at the time.
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It’s believed the last time the two brothers spoke was in 2022, after Queen Elizabeth died.
Fox News' Stephanie Giang-Paunon contributed to this report.