They do seem to have much in common when it comes to their sartorial style, from matching plaid coats to sheer necklines, colour-block designs, and royal blue cocktail numbers.
Check out some of their best twinning moments in the video below...
And now the Princess has been pictured wearing a dress previously worn by Meghan – but there's a twist.
Ahead of the coronation, Madame Tussauds in Australia has updated its royal section, with Kate given a brand new look.
Her waxwork now wears a white Self-Portrait dress featuring long sleeves and a belted waist, and carries a small clutch bag. Her long hair has been styled in Kate's trademark soft curls.
Eagle-eyed fans were quick to recognise the style of the dress. Meghan previously wore the same Self-Portrait design back in 2018 – albeit in red.
The Duchess certainly turned heads when she stepped off the plane at Nuku'alofa airport in October 2018 in Nuku'alofa, Tonga.
At the time, Meghan and husband Harry were on their official 16-day Autumn tour visiting cities in Australia, Fiji, Tonga and New Zealand. Unfortunately, the pregnant Duchess suffered a wardrobe mishap with her outfit, accidentally leaving the return label on the dress.
Kate is a big fan of Self-Portrait and has worn their designs on a number of occasions, including at the Platinum Jubilee Concert last year when she stepped out in a cream tailored boucle and chiffon midi dress and blazer.
Of course, royal fans have now turned their attention to the upcoming coronation and the speculation surrounding Kate’s outfit of choice.
According to The Times, Princess Kate will not wear a tiara to the historic ceremony at Westminster Abbey, but may instead wear flowers in her hair, which would reflect "King Charles's belief in the importance of sustainability and his love of nature".
While we will have to wait until Saturday morning to find out whether Kate will or won't have a tiara moment, the Princess did give a hint about the outfit she has chosen in a chat with This Morning host Alison Hammond, when the pair met during William and Kate's joint outing to Birmingham in April.
Alison disclosed on This Morning that she and Kate had spoken about the coronation, telling viewers: "I said, 'What are you wearing for the coronation?' Because I said to her, 'I'm feeling like you're going to wear blue.'"
Kate reportedly replied: "There is a hint of blue!"
The comment had royal fans speculating on social media on which outfit we could see the Princess wear for the historic occasion, but Kate could have also been alluding to another accessory.
At the state banquet and Diplomatic reception last year, the Princess donned a blue sash, which signifies her position as a Dame Grand Cross of the Royal Victorian Order, the highest ranking of chivalry personally awarded by the late Queen Elizabeth II for being in her service.
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