Prince Charles
Prince Charles and Meghan Markle praise each other. Pictured: Prince Charles, Camilla Parker Bowles and Markle attend The Prince of Wales' 70th Birthday Patronage Celebration held at Buckingham Palace on May 22, 2018 in London. Getty Images/Chris Jackson

Meghan Markle and Prince Charles have built a great relationship as father and daughter-in-law.

It was reported earlier that Prince Charles has a nickname for his newest daughter-in-law. The Prince of Wales reportedly calls the Duchess of Sussex "tungsten" because she is "tough and unbending."

"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 soft," a royal insider said.

According to Martina Bet, a journalist for Daily Express, Prince Charles was also heard praising Markle in a conversation with friends.

"She is so intelligent and so nice. She makes Harry happy," the next-in-line to the throne said. "We could not like her more."

If Prince Charles appreciates Markle, the former "Suits" actress has the same affection towards her father-in-law. According to reports, Markle encouraged Prince Harry to invest in his relationship with his father.

"Meghan met Charles and was bowled over by his charm," the source said. "She told Harry he was wonderful: welcoming, warm, hard-working, kind and stable. She made it clear that he should appreciate him and bond more."

Markle has a great relationship with Queen Elizabeth II and Prince Philip, too. "She has developed an increasingly close, warm relationship with [both] the queen and her father-in-law, Prince Charles," an insider said. "She wants to please them and is doing whatever she can to educate herself to make sure she doesn't put a foot wrong."

While the new duchess has a warm relationship with the royals, she reportedly stopped talking to her dad. According to Markle's father, Thomas, they haven't talked to each other for the longest time. In fact, he was afraid to die without ever speaking to his daughter again.

"I could actually die soon. Does she want this to be the last thing we've said to each other?" Thomas said. "It is probably the longest time I have gone without speaking to her ever. I just want to clear the air and tell her how proud I am of her."

According to an insider, Price Harry and Markle were frustrated about Thomas continuing on making paid interviews. Thomas recently said that he wants to fly to London to meet the Duke and Duchess of Sussex.