Today marks Prince Harry and Meghan Markle's eighth wedding anniversary.

The world's attention was focused on Windsor when the Duke and Duchess of Sussex exchanged vows at St George's Chapel in Windsor Castle before the royal family and numerous high-profile celebrities.

Since that day, the couple have stepped back from their positions as working members of the royal family and relocated with their now two children to the US.

Although Meghan Markle and Prince Harry withdrew from royal duties five years ago, there was a time when Meghan seemed extraordinarily close to her husband's relatives, especially her father-in-law, King Charles.

During their first encounter, the King was reportedly thoroughly impressed by her confidence.

Members of the royal family have historically employed distinctive nicknames among themselves, each possessing a significant story behind it.

While many senior working royals have unique nicknames used in private, one especially unusual nickname has persistently captured the fascination of dedicated royal observers, reports the Liverpool Echo.

The relationship between Meghan and Charles developed substantially over time, with Charles eventually offering to escort Meghan down the aisle during her 2018 Windsor wedding ceremony, after her own father's inability to attend the occasion.

Before the ceremony, a royal source disclosed the distinctive name Charles had selected for Meghan, revealing the unusual yet significant reasoning behind it. Within royal expert Katie Nicholl's book The New Royals, she reveals how Charles had consistently acknowledged Meghan's formidable character, granting her a fitting nickname to reflect this trait.

Nicholl wrote: "Charles reportedly nicknamed his future daughter-in-law 'Tungsten' because of her toughness and resilience." This isn't the first time Charles' distinctive nickname for Meghan has come to light, as the Daily Mail reported in June 2018 that Charles christened Meghan 'Tungsten', a reference to the hardwearing metal, characterising her as "tough and unbending."

A source told the Mail on Sunday at the time: "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."

While Harry and Meghan's wedding was a spectacular affair with the entire royal family present, questions about their relationship continued to linger, as bombshell fresh allegations from a royal expert have emerged.

Royal author Sally Bedell Smith disclosed that one of Queen Elizabeth's cousins and close confidants made numerous comments questioning the genuine nature of the couple's romance in the lead-up to their high-profile wedding, implying Meghan had "engineered" their partnership.

Bedell Smith wrote that Lady Elizabeth Anson said just days before the nuptials: "We hope but don't quite think she is in love. We think she engineered it all," adding: "It's worrying that so many people are questioning whether Meghan is right for Harry.

"The problem, bless his heart, is that Harry is neither bright nor strong, and she is both. Meghan is clearly brighter than Harry, but she has to be careful not to overshadow him."

According to Bedell Smith, Lady Anson characterised Meghan as "full of charm" alongside being "intelligent and thoughtful" when she and Harry first announced their engagement in 2017, yet as the ceremony drew nearer, relations between the late Queen and the Sussexes started to break down.

Bedell Smith disclosed Lady Anson informed her the former monarch had been left 'dismayed' by particular decisions concerning the wedding preparations, and had become "very worried" about her 'weak' and 'besotted' grandson.

She claims the former monarch was left taken aback after Harry had asked the Archbishop of Canterbury to officiate the ceremony without first consulting the Dean of Windsor, with the now Duke of Sussex apparently thinking his grandmother could simply "do what she wants".

Bedell Smith maintains Lady Anson suggested Harry had subsequently "blown" his relationship with his grandmother.

She writes that Lady Anson told her several months before the wedding: "She [the Queen] said she was really upset. I was shocked when the Queen told me this, how she was so saddened." Nevertheless, the author goes on to claim that several weeks before the wedding, Lady Anson told her that Harry and his grandmother had "patched things up".