Princess Kate looks barely recognisable with golden blonde hair in unearthed photo

The Princess of Wales ' beautiful brunette hair has become equally synonymous with her royal image as her immaculate wardrobe.

The 'Kate effect' has influenced women's haircuts for decades, which showed no signs of slowing when the royal debuted a fresh set of face-framing curtain bangs in September last year.

As a senior member of the royal family and future Queen Consort, the Princess has done little by way of 'hair transformations' over the years, staying loyal to her signature chocolate brown 'do and only altering it slightly in the 13 years she's been married to Prince William .

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However, rare photographs unearthed from Kate's childhood show that the royal once sported bright blonde hair...

Ahead of her fairytale royal wedding to the Prince of Wales in 2011, Kate's father Michael Middleton shared a series of photographs of his daughter from her childhood.

© Shutterstock / The Middleton Family

In one snap of the Princess aged four with her father Michael and sister Pippa in Jerash, Jordan, both Kate and her younger sister have golden blonde hair.

The royal's windswept blonde locks, which were likely due to her age, could also have been caused by natural bleaching of the sun in Jordan, where she spent the early years of her childhood growing up.

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The Princess of Wales' hair secrets

There are few royals with hair quite as captivating as that of the Princess of Wales. Ever since she emerged on the scene as Prince William's university sweetheart, Kate's glossy brunette tresses have long been the envy of royal fans who have tried to uncover exactly how the royal achieves her signature healthy curls.

© Max Mumby/Indigo

From suggestions she has hair extensions to evidence of her hair-thickening highlights adding depth and dimension to her Rapunzel-like mane, experts have offered several insights into the Princess of Wales' hair secrets.

Olia Cutz, hair extension specialist and founder of The Extensionist , previously told HELLO! that the royal's tumbling waves could be down to a nearly-undetectable type of hair extension.

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"If she does have extensions, she could have had individual strands of keratin bonds as you can hide them perfectly and no one will ever see them, even if you wear your hair up," explained Olia.

"Kate could easily have had tapes or ultra bonds, which are incredibly tiny strands of hair extensions. They can add thickness and length to any hair type, but are so subtle they are incredibly hard to detect."

After her latest appearance, Michael Gray, award-winning hair stylist for John Frieda spoke to HELLO! about the Princess' subtle blonde highlights.

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"The Princess has introduced some subtle highlights in a balayage form to give the illusion of her hair being lighter and brighter for summer," he explained.

"Still keeping the depth in places, along the parting, and underneath around her neckline where you can see the highlight pop subtly. I love the placement and how the hair hasn’t been lifted too much, for it to look bold or strikingly noticeable. Her hair is toned beautifully and it complements her base colour and skin tone, with a soft caramel shade."