King Charles' sweet nickname for 'tough, resilient' Meghan Markle

Before Meghan Markle's relationship with the royal family went south, she and King Charles reportedly shared a special bond in which he gave the Duchess of Sussex a sweet pet name.

Royal expert Katie Nicholl's book The New Royals, revealed how King Charles held deep admiration for Meghan's character and gave her a nickname which reflected her "toughness and resilience".

"Charles reportedly nicknamed his future daughter-in-law 'Tungsten' because of her toughness and resilience."

Previous reports also suggested that the current monarch expressed his love for his daughter-in-law, by calling her Tungsten, a type of metal whose qualities reflected the Duchess's "tough and unbending" character.

"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," a source told Mail on Sunday at the time.

The strange moniker isn't rare for the royal family as members often used unique and often times confusing names to express their admiration.

The late Queen Elizabeth often used names like 'cabbage', 'sausage', 'Gan Gan' and more as a way to express her endearment.