Their chemistry and connection was said to be instant and now an unauthorized new biography called The Duchess: The Untold Story by royal reporter Penny Junor shows just how much Prince Charles pined for Camilla Parker Bowles when they first met before their affair.

Speaking to the couple’s inner circle, Junor has unearthed a series of explosive stories, which have been published in The Daily Mail.

MORE: Prince Charles “Made a Huge Mistake” Marrying Princess Diana

According to the book, Prince Charles was devastated when Camilla decided to wed army officer Andrew Parker Bowles in 1973.

prince charles camilla parker bowles getty images

Charles and Camilla in 1979.

The pair had met two years earlier after being introduced by Lucia Santa Cruz and hit it off, but Charles’ beloved great uncle and trusted confidant, Lord Mountbatten, advised him against pursuing anything more serious as she wasn’t “sufficiently aristocratic” or a virgin — two very important things back in those days when selecting a royal bride. Despite this, the Prince of Wales still harbored a very deep love for Camilla.

When news of her engagement broke, Camilla penned a letter to Charles while he was working for the Royal Navy in the Caribbean. Her news did not go down well with the royal.

“She wrote to Charles herself to tell him. Her letter broke the prince’s heart. In great distress, he fired off anguished letters of his own to his nearest and dearest.”

MORE: Prince Charles Mourns the Death of His Godmother Lady Mountbatten

“It seemed to him particularly cruel, he wrote in one letter, that after ‘such a blissful, peaceful, and mutually happy relationship’, fate had decreed that it should last a mere six months,” an excerpt of the book reveals.

“I suppose the feeling of emptiness will pass eventually,” a broken-hearted Charles apparently told friends.

Like something out of a rom-com, Charles made a “last-ditch” effort and wrote Camilla a letter begging her not to marry Andrew just a week before they were due to wed in July 1973.

It didn’t work but the pair remained close friends before things progressed into an affair around 1978, shortly after Camilla welcomed her daughter, Laura.

“Andrew was in no position to complain; and when he discovered what was going on, he wisely didn’t make a fuss,” the biography explains.

MORE: Prince Charles Turned to Friend Nancy Regan During Demise of His Marriage to Princess Diana

“Some would say that a part of him actually quite enjoyed the fact that his wife was sleeping with the future King; he might have felt differently had Charles been a traveling salesman.”

As for why Charles was so enamored with Camilla, according to Junor “he loved the fact that she smiled with her eyes as well as her mouth, and laughed at the same silly things as he did. He also liked that she was so natural and easy and friendly, not in any way overawed by him, not fawning or sycophantic.”

prince charles camilla parker bowles getty images

Charles and Camilla in 2005.

“In short, he was very taken with her, and after that first meeting he began ringing her up.”

Of course, Princess Diana was well aware of their dalliances and as Junor writes in her book, in the lead up to Diana and Charles’ wedding in 1981, her jealously came to the fore.

“There were terrifying rages, temper tantrums, hysterical tears for no apparent reason, and her moods changed in a flash,” Junor writes.

MORE: Camilla Parker Bowles Was Housebound for a Year After Revealing Prince Charles Affair

“She became jealous — obsessing about Camilla and turning against people she’d appeared to like, convinced they were out to get her, undermine her or spy on her.”

It wouldn’t be until after Diana’s death and the breakdown of Camilla’s marriage to Andrew that the pair would finally give their romance a proper shot. In 2005, Charles and Camilla wed in a civil ceremony.

Parts of this story originally appeared on NowToLove.com.

More From Closer Weekly

Prince Charles Doesn’t Spend a Lot of Time With Grandchildren Prince George and Princess Charlotte

Prince Charles Thought Prince William and Kate Middleton Were “Tasteless” Newlyweds

See Stunning Photos From the Most Iconic Royal Weddings Ever!