Prince Charles and Thomas Markle Sr. have different nicknames for Meghan Markle.

Thomas appeared on ITV's "Good Morning Britain" on Monday. According to him, he calls his daughter "bean" or "beanie" because of her small size.

"When she was a child she loved 'Jack and the Beanstalk,'" Thomas said. "Because she's so small we called her "bean" or "beanie" and eventually it becomes beanie and the beanstalk. So, I called her 'beanie'."

During the interview, Piers Morgan asked Thomas if he calls his daughter duchess, now that she's officially a royal after her wedding to Prince Harry.

"No," Thomas replied. "I don't think I'll call her duchess. I don't have to, she's my daughter."

On the other hand, Markle's father-in-law, Prince Charles, has a unique nickname for her, too. The Prince of Wales reportedly calls her "tungsten" because she is "tough and unbending," a palace source told Daily Mail journalist Charlotte Griffiths.

"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. It's become a term of endearment," the source said.

Prince Charles and Markle's close bond has become apparent when the next-in-line to the throne opted to walk her down the aisle after Thomas decided to cancel his attendance at the royal wedding. Thomas had to recover from a major heart surgery, so he opted to witness the event on TV. In his recent interview, he said that there was no better replacement for his absence than Prince Charles.

"It was incredible watching her," Thomas said on ITV's "Good Morning Britain". "I was very upset that it wasn't me [walking with her], but the whole world was watching my daughter. I was very happy about that. The unfortunate thing for me now is I'm a footnote in one of the greatest moments in history rather than the dad walking her down the aisle. That upsets me somewhat. … I absolutely wanted to walk my daughter down the aisle. [But] I can't think of a better replacement than someone like Prince Charles."

Thomas also revealed that Prince Harry and Markle want to have babies soon. But royal commentator Angela Levin didn't like his revelations on national television. According to her, Markle will be "horrified" of her dad's interview.

Meghan Markle
Prince Charles and Meghan Markle's father, Thomas, have different nicknames for the Duchess of Sussex. Pictured: Markle and Prince Harry attend the prize ceremony of Royal Ascot Day 1 at Racecourse on June 19, 2018 in Ascot, United Kingdom. Getty Images/Chris Jackson