The new-age princess

Once she's fully initiated into the Royal Family's inner circle, she'll also have advisers to help guide her choices, he says. And Mr Bryce sees a day, possibly as early as next year, when the Queen will step down from her official duties.

This will mean Prince Charles and his sons, William and Harry, will have to shoulder more of that work, he says.

Of all the royals, Princess Anne has consistently shown the greatest dedication to her causes, performing more engagements each year than any other member of the family. Those visits and engagements don't make the papers that often but she's the busiest, says Mr Bryce.

Both Diana, the Princess of Wales, and the Duchess of Cambridge married into the Royal Family at a younger age - Catherine was 29 and Diana was just 20. At 36, Meghan is fully-formed, she's older, she's used to the public eye, says Mr Bryce. By contrast, in the early years, Diana was "like a fish out of water".

"She had nothing to do, her marriage was not what it should be and it was the Duke of Edinburgh who pointed her towards doing something," he said.

By the time of her death at 36, Diana had used royal visits around the world to show empathy to the ill and impoverished, and overturned the image of the royals as aloof. In particular, she had challenged the public's perception of HIV and Aids by shaking patients' hands.

The Duchess of Cambridge has also taken time to build up her portfolio since her marriage to Prince William - and is demonstrably keen to support the arts and children's causes including a hospice, the Scouts and tackling cyberbullying.

"Kate has been the big royal story for a while but Meghan might elbow her off the stage," says Mr Bryce. He believes Meghan will fast become the biggest royal ticket, drawing interest in the UK and in the US.

"She has not got the fragility of Diana so will never achieve the saintly reverence, but she will attract that level of interest. It's going to be massive.

"The public will realise that unlike Princess Diana who was learning as she went along, Meghan Markle will step up to the job and be off and running."

Elizabeth Nyamayaro agrees. With her grace, ability to listen and passion to make social change, "she'll be fine - she'll be great in fact".