This £7.99 nail polish loved by the Queen and Duchess Catherine is on sale right now

• The Queen has reportedly worn the Essie shade since the eighties
• The Duchess of Cambridge is also thought to be a fan of the brand
• In other royal news, The Duchess of Cambridge is under "extra pressure", according to a body language expert

It's very well-known that Queen Elizabeth favours a classic shade of Essie nail polish for her manicure-of-choice. 

According to HELLO!, Her Majesty has worn the very subtle Ballet Slippers shade since 1989. And it makes total sense, as the monarch reportedly likes a neutral nail, and this is a chic and understated colour.

Ballet Slippers, a very light, sheer pink, is an excellent go-to as it's guaranteed to go with any outfit and any occasion – for a little added "something". Even better, it's currently on sale as part of the ASOS Black Friday deals.

The Duchess of Cambridge is also thought to be a firm fan of the brand, choosing Essie for her wedding day manicure. Duchess Catherine's manicurist, Marina Sandoval from the Jo Hansford salon, shared the exact shades of polish that she blended for the royal wedding on the Daily Mail.

Sandoval mixed Bourjois So Laque Ultra Shine Nail Enamel in Rose Lounge, a barely there pink (now discontinued), with Essie Allure ($9, essie.com), a sheer beige tone.

The Queen's hands are rarely on show as she often chooses to wear a set of gloves. However, when Her Majesty's bare hands are on view, you can pretty much guarantee that you'll never see a bright nail colour.

Essie nail polish was launched in 1981 by Essie Weingarten and, according to the brand's website, the Queen has been wearing the Ballet Slippers shade since 1989. 

It adds that Queen Elizabeth's hairdresser sent a letter to the brand requesting that specific shade because it was the only colour Her Majesty would wear. It's described as "an iconic colour for all the seasons" – and rightfully so.

In fact, the Queen's rule has become somewhat of a tradition for all female members of the royal family since then. It is thought to be protocol that Catherine, Meghan, Beatrice, Eugenie and co tend to avoid bright shades of nail polish in order to maintain the royal sense of formality.

Little is known about the Queen's beauty secrets, but over the years there have been few rumours.

Her favourite flowers are reportedly carnations and, while the exact scent of perfume she buys has not been revealed, she is thought to be a regular of Floris London, which was first granted the royal warrant 1820.

The brand maintains a level of discretion when it comes to exactly what the Queen orders but they did reveal to the Telegraph that the Queen orders from across the core range. Fragrances start from around £55.

When it comes to the Queen's lips, she is partial to the odd pop of colour. But her go to brand is thought to be Elizabeth Arden. The brand has held a royal warrant for over 50 years. The Telegraph speculates that Elizabeth Arden's Beautiful Colour Moisturising Lipstick Matte Finish Extension in Bold Red is a firm favourite of the Queen. She is also a reported fan of this best selling skincare product.

While the Queen clearly likes to keep her beauty secrets under wraps, but we do know that her nail polish of choice remains unchanged. Why not treat yourself to the same shade? If it's good enough for Her Majesty...