Royal expert Katie Nicholl in her book "The New Royals" revealed what British Monarch used to call the Duchess of Sussex. The book reveals that King Charles III gave his daughter-in-law a nickname because of her "toughness and resilience." The monarch called his future daughter-in-law "Tungsten," Katie Nicholl wrote in her book.

Tungsten stands for a hard steel-grey metal of the third transition series that has the highest melting point of all metallic elements.

According to Page Six report, King Charles III's opinion was formed after the 'Suits' alum showed perseverance during her and Prince Harry's 2018 appearance at the Royal Foundation Forum.

Nicholl in her book wrote, "It was, according to one aide, the moment William and Kate, who was heavily pregnant, realized they needed to up their game." She added, "The Cambridges [now named the Prince and Princess of Wales] had already signalled their intention to be more than 'ornamental royals' and had, along with Harry, made a huge success of their mental health campaign Heads Together."

She continues, "But Meghan was the breakout star of the foursome. She was polished, passionate and funny, using all her TV-honed skills to present her case. That was a wake-up moment for William and Kate when they realized that Meghan was very impressive, very confident and very capable, according to a source."

King Charles used the nickname four years ago, and it's unclear whether he calls Meghan Markle by the same nickname.

Meanwhile, a new edition of Meghan Markle's Archetype podcast, which launched last month with Serena Williams as the guest, has finally come out. The most recent episode followed a discussion on toxic Asian stereotypes featuring journalist Lisa Ling and actor-comedian Margret Cho.