The British royal was just 12 years old when she passed away in August 1997 after a car accident in Paris, France.
At an event held in aid of the Heads Together mental health charity he set up with his brother Prince William, 34, Harry conversed with former England soccer star Rio Ferdinand, whose wife Rebecca Ellison died after battling cancer last year, about how they'd dealt with losing people close to them.
SHELL SHOCKED: Prince William and Prince Harry at Westminster Abbey for the funeral of their mother Diana, the Princess of Wales on September 6th 1997. PHOTO: WENN
According to the BBC, the Prince, 31 told Rio that he regretted that he'd only spoken in public about his feelings in relation to his mother's death after he was 28 years old, saying, "You know, I really regret not ever talking about it."
Speaking at the event he told the broadcaster of his admiration for the soccer star for discussing mental health issues after the loss of his spouse.
"It is very easy for someone to look at someone like Rio Ferdinand and say, 'You get paid all the money in the world, you are a successful footballer, you have fast cars.' But at the end of the day his wife was snatched from him at an early stage of his life with her," Harry said. "So of course he is going to suffer, it doesn't matter if he has an amazing job."
Rio, 37, spoke of how he related to the Prince due to his three young children having to cope with the death of their mother at a young age.
"He's gone through different stages in his life that my kids are going to be going towards," the ex-soccer star said. "So to get some of his experiences is very rewarding for me and very educational in many ways."
After his long years of public silence over the death of Diana, whose passing sparked an outpouring of grief in the U.K. and across the world, the royal and his brother have increasingly opened up about their feelings in interviews.
In March, 2016 he appeared on U.S. breakfast show Good Morning America, saying that he hoped his mother would be proud of his charity work.
"I hope she's looking down with tears in her eyes, being incredibly proud of what we've established, I suppose," he shared. "I'm sure she's longing for me to have kids so she can be a grandmother again, but I hope that, once again, everything we do privately and officially, that it makes her proud."
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