The author claims that King Charles and Princess Diana were in a "mortal combat" over Camilla before eventually developing "lasting affection."

Despite their marriage not lasting, King Charles and Princess Diana's admiration for each other persisted.

The UK Times reported that the late Princess of Wales wanted to convey the authenticity of her affection for her ex-husband despite their divorce.

After parting ways, Christopher Andersen, author of "The Day Diana Died," revealed that the couple grew closer once they were permitted to seek love elsewhere.

Andersen stated that Charles and Diana's marriage was marked by constant conflict over Camilla, the woman Charles truly loved. Their fights were legendary, and Diana's desperation led her to become bulimic and attempt suicide several times. Despite this, their relationship was one-sided from the start.

Andersen remarked that the marriage of Charles and Diana was a stunning disaster.

Diana and Charles, despite their initial animosity following their divorce, eventually developed a mutual respect for one another. They were the parents of Prince William and Prince Harry.

"Charles and Diana spent their entire married life locked in mortal combat over Camilla, the woman Charles truly loved." — Christopher Andersen, author of "The Day Diana Died"

Diana wanted to convey that there was once a genuine love between her and Prince Philip, according to Ingrid Seward, editor-in-chief of Majesty magazine.

According to The Times, Seward stated that Diana revealed her wish for people to view her love letters from Charles just before her death.

"Seward continued, "She wanted people to know that she loved Charles and he loved her. She also wanted the boys to know about their great love period.""

Diana spoke about the letters just a few weeks before her death, according to Seward, who claimed that Diana wanted the early days of her romance with the heir to the throne to be properly reflected.

Last year, People magazine reported that some of Diana's intimate letters to friends during her divorce were sold at auction for just under $170,000. However, it is unclear which years these letters were written and their current whereabouts are unknown.

In 1981, Diana and Charles got married after a brief courtship. The princess stated that they only met 13 times before he proposed, according to People magazine. They later welcomed their son William in 1982 and Harry in 1984.

In 1992, Andersen observed that the mood between Charles and Diana became softer after their separation. Their divorce was finalized in 1996.

"When the pressure of maintaining the charade as husband and wife ceased, Charles and Diana were finally able to be themselves, Andersen explained. Diana was ecstatic with her new love, Dodi Fayed, although she had no plans of marrying him. Meanwhile, Charles would eventually be free to marry Camilla."

"Andersen emphasized that Charles and Diana had no desire to reunite, and in fact, they were able to establish a warm and caring relationship as exes. Their shared concern for William and Harry led to true, lasting affection between them."

Andersen claimed that Diana finally accepted Charles' relationship with Camilla.

"Andersen stated that Diana developed a grudging respect for Charles' love for Camilla only after their divorce. She told William, "When you find a true, deep love like that, it's a precious thing. You've got to hold on tight to it." Despite their tumultuous relationship, Diana and Charles' bond grew stronger in the final months of her life, as she and her new boyfriend, Dodi Fayed, made headlines globally for their yacht vacation in the Mediterranean."

"In July 1997, when Gianni Versace was shot outside his Miami Beach estate, Charles contacted Diana to express his sympathy. Diana then informed her close friend Lucia Flecha de Lima that the rift between them had been resolved."

"Charles invited Diana and their sons William and Harry to join him aboard the royal yacht Britannia later in the year for a segment of its final voyage before being decommissioned. Diana was thrilled and touched by the gesture, which marked the last time Charles and Diana spoke."

Charles wrote a letter to Diana, but she never received it.

Andersen stated that on August 30, 1997, Charles wrote a letter to 'My Dearest Diana' in his study at Balmoral, asking if Harry, who was facing difficulties with his studies at boarding school, should be held back an extra year before joining William at Eton.

"Charles, the future King, sealed the note with "Lots of Love" and instructed his secretary to deliver it to Kensington Palace so that Princess Diana could find it on her desk upon her return from vacation."

The following day, Diana met a tragic end in a car accident in Paris. She was 36 years old. Her unexpected demise left the world in shock, including her ex-husband.

"Andersen said that it hit Charles particularly hard when he learned that Diana's mother was the one who had died. He was devastated because she was the mother of his children. When he went to Paris to retrieve Diana's body, he almost collapsed at the sight of her. A nurse who was in the room said that Charles reeled back as if struck by an unseen hand and began to faint."

"According to Andersen, it was Charles who bravely confronted Queen Elizabeth II and palace officials after Diana's death, insisting on a royal funeral for her, despite the late queen's initial reluctance due to Diana's loss of royal status following the divorce."

Over 2 billion people worldwide watched the ceremonial funeral of Diana, which was attended by 2,000 people.

It's likely that Charles has had regrets about his marriage to Diana over the years, as Andersen stated.

To comprehend the heartbreak of Diana's marriage to Charles, one must go back to the start, Andersen stated. Just as Kate Middleton and countless others adored William and pinned pictures of him on their walls, dreaming of marrying the dashing prince, Diana and her peers fantasized about marrying [the former] Prince Charles. At just 19 years old, Diana became engaged to Charles, and despite her clear love for him, it was evident that he was still in love with Camilla.

"Charles famously responded to being asked if he loved Diana during a TV interview following their engagement with the phrase "whatever 'in love' means." In contrast, Diana immediately declared her love for him. Although there may have been instances where Charles expressed affection towards Diana, their marriage was a nightmare for both of them from the start."

The marriage between King Charles and Princess Diana was so explosive that violence seemed inevitable, according to a bodyguard's allegations.

During Diana's second pregnancy, there was a brief period when she and her husband became close. Diana considered it the closest they had ever been or would ever be. However, this closeness ended as soon as their son Harry was born. Charles, who had hoped for a girl, made an insensitive comment about Harry's red hair, causing Diana to shut down emotionally.

"Charles definitely regrets being bullied by his father Prince Philip into marrying Diana, which would have meant that William and Harry never existed. The truth is, Camilla was the love of Charles' life all along, and Diana knew it."

In 2005, Charles married Camilla, and in 2022, he ascended to the throne after his mother's death. Camilla was crowned queen in 2023.

The Associated Press contributed to this report.