The actress, who has just finished filming US legal drama Suits, is expected to move to the UK imminently to be with Prince Harry, returning to the land of her distant paternal ancestors.
Her family tree has already been researched by television documentaries and newspapers as her relationship with the Prince moved closer to a rumoured engagement, with revelations that some of her ancestors on her father's side hailed from the coal mining areas of Yorkshire, while her mother's forebears were traced to a slave forced to work on the Georgia plantations before being emancipated with the abolition of slavery in 1865.
Ms Markle and the Prince are, it is claimed, distant cousins through a mutual ancestor: High Sheriff of County Durham Ralph Bowes, born in 1480.
Michael Reed, a Australian teacher and amateur historian who has made a study of the modern Royal Family and their connection, has gone one step further, to find evidence of the Markle family's connections to the royalty of Tudor England.
Curiously, he believes the Markle family may already be aware of the connections, after coming across independent research by a Mike Markle, understood to be the actress' great-uncle, online from 20 years ago.
His own investigations have taken the family tree back to John Plantagenet, King of England who lived from 1166 to 1216, in a line which includes John Hussey, 1st Baron Hussey of Sleaford born in 1465.
An illustrious career saw Lord Hussey knighted in the field for his loyalty to Henry VIII at the Battle of Blackheath, work as a diplomatic envoy, made esquire of the body and chamberlain to the King's daughter Princess Mary.
He was later present at the christening of Princess Elizabeth, carrying the canopy over her, His fall from Royal favour came after the 1536 Pilgrimage of Grace, a rebellion against Henry VIII he was unable to successfully put down.
His loyalty called into question, he was found guilty of treason, imprisoned in the Tower and eventually executed.
Mr Reed first came across intriguing snippets of information while researching America's Founding Fathers and Nantucket while he was teaching a course on the subject.
Reading up on Christopher Hussey and his family, he recognised the name "Markle" on a geneology forum also investigating the same family tree.
Mr Reed had been particularly interested to read about Ms Markle's family history, he said, after previously researching the forebears of Kate Middleton, who went on to become Duchess of Cambridge.
There too he found Royal connections, with two of her father Michael's relations baronesses who were invited to successive coronations.
"You can't just look at one parent," he said. "You must look at both sides to get the full picture.
"It's incredible that Meghan's great-great-great maternal grandfather was a slave and the other great-great-great paternal grandmother was a New Hampshire landowner, who had royal blood."
The research comes amid mounting speculation that Ms Markle could become the next so-called "commoner" to marry into the Royal family thanks to her blossoming relationship with Prince Harry.
The actress has finished filming Suits, shut down her lifestyle blog and reportedly ended her advertising contracts in indications she could be about to move to the UK permanently.
In September, less than a year after the relationship was confirmed by Prince Harry, Ms Markle broke her silence with a gushing Vanity Fair interview in which she disclosed: "We're two people who are really happy and in love."
Prince Harry, who remains fifth-in-line to the throne until the arrival of the Duke and Duchess of Cambridge's third baby, must ask the Queen's permission before marriage.
