Princess Eugenie, 28, has asked her older sister, Princess Beatrice, 30, to be her maid of honour on her wedding day.
The sisters are not only close in age, but have often hinted at their close relationship.
As the pair have grown up, they’ve gone on to forge their own identity – from their very different careers to their style.
So, how has their individual styles changed over the years?
Like many siblings of a similar age, Princess Eugenie and Princess Beatrice were spotted in very similar ensembles as youngsters.
In one snap, released by the younger royal ahead of her wedding, the pair could both be seen wearing white dresses.
The two were starring as bridesmaids at the wedding of their former nanny, and can be seen with matching flowers.
During their many public appearances, Princess Eugenie, a director at the Hauser & Wirth art gallery, and Princess Beatrice, who is reportedly a business consultant, opted for very different looks.
In 2011, the pair were pictured celebrating what would have been Freddie Mercury’s 65th birthday – 20 years after he passed away.
Princess Eugenie donned a mid-length red dress for the occasion, which featured a bandeau neckline.
She added sparkle to the aesthetic with the help of a glittery silver bolero.
Meanwhile, Princess Beatrice rocked her own style in a purple dress, which featured a tight-fitting bodice and sheer sleeves.
Back in 2016, the pair were pictured at the National Service Of Thanksgiving to mark their grandmother Queen Elizabeth II’s 90th birthday.
While they both opted for a bold look, they differentiated their style through colour and pattern.
Princess Eugenie stepped out in a vibrant red dress, which was plain except for a cut-out design at the top.
Meanwhile, Princess Beatrice donned an attention-commanding monochrome coat dress, which featured geometric print.
Despite having opted for very different outfits at events over the years, the duo channelled a summery elegant look at Trooping The Colour in 2017.
Both wearing pale-toned hues, Princess Eugenie’s pink blouse had been embellished with flowers, while Princess Beatrice’s baby blue garment had a similar design.
The two royals were also pictured together back in May this year, at the wedding of their cousin, Prince Harry, 34, and Meghan Markle, 37.
At the time, the pair both sported blue ensembles – but that’s not to say the two outfits could have clashed.
Princess Eugenie opted for a summer-inspired pale blue Gainsbourg shift dress, which featured two pockets.
Meanwhile, her sister’s gown was of a deeper shade – a teal Roksanda number which had been adorned with bubble detail.
The outfit, which retailed at £12,000, also had billowing sheer sleeves.