Meghan Markle reportedly turned down the Queen's offer to be "shown the ropes" when she was first introduced into the Royal Family.
According to UK author and Queen Elizabeth II's friend Gyles Brandreth, Meghan was given the chance by the monarch to be helped ease into the way of life before she married Prince Harry.
The Queen hoped Sophie the Countess of Wessex would be able to instruct the actor about some of the trickier aspects of royal life as she was dating Harry.
In an extract of Elizabeth: An Intimate Portrait, which is being serialised in the Daily Mail, Brandreth says the Queen was initially very welcoming of Prince Harry's then-girlfriend.
"The Queen (who, of course, had seen it all before) understood that Harry's girl might find adjusting to royal life 'challenging to begin with' (as she put it)," he wrote.
"'It is very jolty, but you soon get used to it' - that was Her Majesty's experience going back many years.
"To help Meghan, the Queen suggested that her daughter-in-law, Sophie Wessex, would be an ideal mentor. 'Sophie can help show you the ropes,' said the Queen.
"Meghan made it clear that she did not feel she needed Sophie's help. She had Harry."
Brandreth claims the Queen "was a little concerned at that".
Sophie was thought to have been the perfect person to guide Meghan through the intricacies of her new life, as she had run a PR firm for five years, prior to marrying Prince Edward in 1999.
Brandreth also wrote the Queen was "concerned" again when "word reached her that Meghan was reportedly occasionally a bit 'high-handed' with staff".
"The Queen put it down to pre-wedding nerves," he said.
