There are certain royal traditions royal family members must abide by when it comes to interacting with the Queen, and the Duchess of Cambridge has broken a big one.

On Monday, Duchess Kate was joined by the Queen and other royal family members, including her husband in support for a project she had been working on for a number of months, her Back to Nature garden.

While the royal gave a grand tour of the incredible displays and pointed out key features of each garden, the grandmother-in-law smiled and nodded in approval.

But before the quick journey around the Chelsea Flower Show began, Duchess Kate made a grand gesture of kissing her grandmother-in-law on both cheeks, followed by a quick curtsy.

The moment, albeit a sweet one, is a big no in the world of the British royals.

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A post shared by Catherine Duchess Of Cambridge (@katemiddleton_kurdistan) on May 20, 2019 at 10:17am PDT

The tradition goes, all women in the royal family are required to curtsy before the Queen – and although it may seem minor, Duchess Kate’s quick decision to greet her esteemed family member with a royal kiss instead tells a bigger story about the dynamics of their relationship.

For the mother-of-three to be able to address Her Majesty with such an informal greeting spells a massive tick of approval.

Although it is a minuscule moment, one the Duchess may have gotten mixed up whilst in a public setting, it is more likely she is comfortable enough with the Queen to know her place – after all, image matters deeply to the royal family.

This is not the first time Queen Elizabeth has showed her delight and approval towards the 37-year-old Duchess.

In March, Her Majesty and Kate spent a few hours together for a solo public engagement – one that was not overlooked by royal fans.

Further, on April 29, the royal was bestowed with the highest honour a royal can receive from the Queen – the special title as the Dame Grand Cross of the Royal Victorian Order.

The role is so big, it is the equivalent of being a knight, according to The Sun.

Awards of this level are given personally by the Queen as recognition for their services to the Sovereign.