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If you’re as obsessed with Kate Middleton and Prince William’s clothing as we are, then chances are, you’ve noticed a colorful pattern as well. While the Princess of Wales often repeats stylish clothes and keeps her favorite designers incorporated somehow into her outfit, she also wears a lot of blue with William.

Within the past year alone, Kate and William have arrived in blue clothing about half a dozen times — and experts think they know the reason why!

In fashion expert Rosie Harte’s new book The Royal Wardrobe, she wrote about the color theory behind the Prince and Princess of Wales’ clothing.

“Blue is a more palatable alternative to the colors traditionally associated with royalty, being far less aggressive than red and significantly more conservative than purple,” she said in an excerpt obtained by DailyMail. “It has associations with peace and also modernity, making it a perfect representation of the Waleses’ quest to appeal to both traditional and progressive values in society.”

But Harte doesn’t stop there because she also analyzed Meghan Markle’s royal fashion, saying she seemed “to have picked a color to call their own.” Meghan was often seen at big events in green clothing, with Harte saying, “Green seems to be a common theme in their wardrobes and has made appearances at many of the key moments in their marriage.”

“What meaning does the colour green serve the Sussexes? Practically, it fits very nicely with the other symbolic aspects they’ve chosen to align themselves with,” she said. “The Duke and Duchess like to pose for official portraits outside: it’s far less alienating than a grand palace interior might be and neatly complements their personal interests in environmental causes.”

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