Princess Kate and Melania Trump are set to join forces next week for their first ever joint engagement – a day destined to be etched into the royal fashion history books.

Just four years ago, it was a different American First Lady who stood alongside the then-Duchess of Cambridge.

In June 2021, during a State Visit to meet the late Queen Elizabeth II, President Joe Biden and Dr Jill Biden travelled to Cornwall, where Kate and Dr Biden visited Connor Downs Academy preschool.

Their strikingly coordinated looks – Kate in a raspberry Alexander McQueen dress and Dr Biden in a soft pink jacket – became an instant style moment, showcasing the subtle diplomacy of fashion, especially with the so-called “special relationship” between the UK and the US.

Princess Kate and Melania Trump set to define new style era of US-UK special relationship

Dr Jill Biden and Princess Kate joined forces back in 2021

Next week’s meeting promises to create an even more high-profile spectacle.

Melania Trump, known globally for her meticulous wardrobe and sharp tailoring, will accompany the Princess of Wales at Frogmore Gardens to meet Chief Scout Dwayne Fields and members of the Scouts’ Squirrels programme as the youngsters work towards their ‘Go Wild’ badge.

Kate has been Joint President of the Scout Association since 2020, and her commitment to children’s outdoor education is a key pillar of her public work.

Fashion watchers will be on high alert. Mrs Trump is celebrated as one of the most stylish women in the world - her tenure as First Lady marked by bold silhouettes, couture houses, and striking accessories.

Donald Trump, Queen Elizabeth and Melania Trump pictured at the state banquet in 2019

Melania Trump attending a meeting of the White House Task Force on Artificial Intelligence (AI) Education in the East Room at the White House

Princess Kate, as a future Queen, is equally influential. Her ability to send clothes flying off the shelves within hours has reshaped the British fashion landscape and turned every public appearance into a style event.

On September 17, the Trumps will arrive at Windsor Castle to meet Prince William and Princess Kate before joining King Charles and Queen Camilla for a grand Carriage Procession through the Windsor estate.

Images of the six figures together will dominate front pages worldwide, with particular scrutiny on what Kate and Mrs Trump choose to wear.

Their contrasting yet equally polished wardrobes – Kate’s timeless British elegance and Mrs Trump’s sleek, international glamour – are certain to provide a masterclass in modern diplomatic dressing.

Princess Kate has a very positive impact on the British fashion economy

Melania Trump is regarded as one of the most fashionable women in the world

Later that evening, King Charles will host a glittering State Banquet inside Windsor Castle.

Should Princess Kate attend, tradition suggests she will don a full-length gown and a tiara, pieces often imbued with historical significance and family heritage.

Mrs Trump, whose eveningwear choices have ranged from high-octane couture to minimalist chic, is expected to deliver a look that can stand shoulder-to-shoulder with royal jewels.

The images of these two influential women side-by-side – first amid the splendour of a State Banquet and later in the gardens with Scouts – will be an unstoppable force for fashion admirers and a defining moment in the ongoing dialogue between style and international diplomacy.