When Meghan Markle joined the British royal family, Prince Charles reportedly feared "problems" could arise. A royal author has made the claim.

Royal author of the book titled, "Prince Andrew, Epstein and the Palace" Nigel Cawthrone said that heir to the British throne, Prince Charles admired Meghan Markle. However, the 71-year-old feared that "there's only room for one strong royal woman - the Queen" in the family, The Sun reports.

The Duke and Duchess of Sussex announced their decision to step down as senior royals in January. The couple stepped down officially in March. And, now the family-of-three is isolating in their rented Los Angeles mansion.

"I think he [Prince Charles] likes strong women, but in The Firm there is only room for one Queen. I think he foresaw considerable problems ahead for The Firm. Harry and Meghan amplified the popularity of the royal family in the way that Prince Andrew and Fergie did at the time," said Cawthrone speaking to Fabulous.

"However, for the sake of The Firm he will feel this outcome is better that the monarchy is small in size rather than a constellation of stars in separate orbits," he added.

He said that the Prince of Wales "genuinely made an attempt to support what Harry and Meghan were looking for as long as it wouldn't upset other HRH's. In truth, however, there wasn't a lot he could do apart from offering moral support," Cawthrone added.

The royal author goes on to add that the royal is personally regrets that he won't get to see his son and family as much as he otherwise would have. "He likes tradition and order," Cawthrone said.

Buckingham Palace sources said that Meghan shared a very close bond with her father-in-law since the time he walked her down the aisle during her and Harry's May 2018 royal wedding. The two are said to have a shared interest in art, culture and history.

Prince Harry and Meghan Markle
The couple are said to have relocated to California by private jet earlier this month. Photo: AFP / DANIEL LEAL-OLIVAS

The future king is believed to have a special name for his daughter-in-law Tungsten. The name is inspired by the tough metal known for its robustness and strength. "Prince Charles admires Meghan for her strength and the backbone she gives Harry, who needs a tungsten-type figure in his life as he can be a bit of a softy," reports Mail on Sunday.