So then, THIS is what the Queen has to say about Princess Kate

In three weeks' time, Queen Elizabeth II will become Britain's longest serving monarch – overtaking her great-great grandmother, Queen Victoria.

As of right now, she's been on the throne for an incredible 63 years 192 days: Victoria's record currently stands at 63 years 216 days.

To mark the historical occasion, a new book has been released, The Queen's Speech; a biography which reveals intimate detail of Elizabeth's life – including her sometimes tumultuous relationships with 'the in-laws'.

And while much of the publication deals with the likes of Princess Diana – and the Queen's apparent regular disdain for her – the insight into the royal's relationship with the Duchess Of Cambridge is equally fascinating.

It has been rumoured in the past that the monarch has been judgemental of Princess Kate's 'normal' upbringing and middle class (although also rather privileged) roots.

However, The Queen's Speech dismisses this almost entirely.

In fact, it seems that Elizabeth and Kate get on extraordinarily well – with the former viewing the latter's marriage to her grandson as being much akin to her own long-standing and happy union with the Duke Of Edinburgh. 

As for Kate's lack of 'blue blood,' it seems that Elizabeth is entirely unconcerned; indeed, her own mother, Elizabeth Bowes, was one of ten children born into a line of lesser, Scottish nobility. 

“She thoroughly approves of the Duchess Of Cambridge and doesn’t give a fig for her being from an ordinary, middle-class background,” the book’s author Ingrid Seward writes.

“She has high hopes that the Cambridges’ marriage will be as successful as her own.”

Ms Seward even goes so far as to claim the Queen greatly admires Kate for how well she is handling her transition to life as a princess.

“The Middletons and the Windsors might seem at first glance to be worlds apart,” she writes. “Kate certainly shows no sign of adopting the horsey, doggy lifestyle beloved of her grandmother-in-law.

“But the Queen admires how well Kate has embraced royal life, combining it cheerfully with duty and motherhood. Nothing could matter more.”