Princess Diana had two greatest loves - and Prince Charles was not one of them.

Days before Princess Diana's 25th death anniversary, her only brother, Charles Spencer, spoke up about her passing and revealed some of her secrets - including her true love.

Speaking during his appearance in the new podcast "The Firm: Blood, Lies and Royal Succession," Charles opened up about the men Princess Diana dated. Although he could not name who was the man his sister loved the most, Spencer disclosed that the Princess of Wales' true love was actually two men - her sons, Prince William and Prince Harry.

"I'm always surprised by how difficult August 31 is each year, actually," he said. "I always slightly brace myself for it and it does take me out at the knees. It is a very poignant time.

He added that his sister was the symbol of beauty, compassion, and humanity.

After she died, he reportedly promised her that her family would continue to support and love her sons. With that, Charles was extremely mad when he saw Prince William and Prince Harry walking behind their mother's remains at a very young age.

For the brother, seeing the two young royals suffer the same pain their mother went through made him feel horrified.

Princess Diana got engaged to Prince Charles after having 12 dates with him. Her older sister, Sarah, previously dated the heir to the throne.

However, a day before the royal wedding, the Princess of Wales tried to cancel the event after realizing that Prince Charles was in love with Camilla.

Princess Diana's Tragic Death

Ahead of her death anniversary, several documentaries were aired and unearthed letters were shared with the public.

One of which is British TV network Channel 4's documentary, "Investigating Diana: Death in Paris," which explores the theories surrounding her death.

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"This utterly compelling series explores in forensic detail what happened in the investigations following the death of Princess Diana -what it was like for the detectives working on a huge global news story that was not just a tragedy for the families involved but a massive internet phenomenon too," Channel 4 executive Shaminder Nahal said.

Princess Diana's death got bombarded with several buzzes, including a claim that Prince Charles plotted her death and that she was pregnant when she passed away.

As the last day of the month nears, royal fans have been taking their time to remember Princess Diana and celebrate her life.

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