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Classic up-do - This up-do is perhaps the Princess' most iconic and go-to hairstyle.

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Student days - Not much has changed since Kate's student days in 2005!

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Natural beauty - Taken at a concert celebrating Nelson Mandela's 90th birthday in London's Hyde Park in 2008.

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Long locks - Middleton keeps it simple with a half up-do and long locks in Australia in 2014.

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High ponytail - Kate cuts a sleek figure in a blue tailored ensemble and a high ponytail in New Zealand in 2014.

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Side-swept fringe - Kate rocked wavy hair with a side-swept fringe to visit the Anna Freud Centre in London in 2015.

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Wind-swept perfection - The Princess lets her hair down on her visit down under in 2014.

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Short chop - Kate Middleton shows off a shorter style in Stockholm.

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Glowing inside and out - Her engagement photo shoot in 2010.

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Effortless waves - Effortless waves in Berlin.

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Sleek tuck - The Princess keeps it simple in polka dots.

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Wavy vibes - At Docklands Sailing and Watersports Centre.

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Elegant - She swept her hair up with some subtle volume for the BAFTAs.

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Relaxed structure - A casual hairstyle in February 2017.

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Braided hair band - She sported a fun braided hairdo for the official opening of Haida Gwaii hospital in Canada in 2016.

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Side ponytail - And a side ponytail for a day out greeting children at the Cridge Centre in Victoria, Canada, in 2016.

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Big hair day - A voluminous version for the Heads Together charity event in January 2017.

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Serious waves - The Princess donned some serious waves for an important speech on mental health in 2016.

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Country chic - Middleton embodies country chic in a weatherproof casual outfit and loose hair.

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Half up glamour - A subtle half up-do with minimal accessories and a shimmery gown at the UK-India Year of Culture 2017 event.

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Classic Kate - At the Guild of Health Writers Conference.

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Grace Kate - Middleton oozed Grace Kelly vibes at an event at the British Ambassador's Residence in The Hague, Netherlands, in 2016.

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Breezy waves - The royal opts for loose waves with a centre-parting for a visit to Steward's Academy in Harlow in 2016.

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Weather ready - Another simple half up-do and sunglasses to help control her mane in the unpredictable weather of the Scilly Isles in September 2016.

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Beachy - She opts for loose locks and a soft side-swept fringe for a day event at Newquay's Towan Beach in 2016.

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Sporty pony - The royal sports a casual ponytail for a fun day out at America's Cup World Series in Portsmouth in 2016.

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Loose up-do - The Duchess at a gala dinner for East Anglia's Children's Hospices in the summer of 2016.

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Curls - Middleton sports loose curls for SportAid's 40th Anniversary event in 2016.

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Tighter curls - On a trip to India in 2016, the royal has bouncy curls.

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Boho flair - In Bhutan in 2016,  a more relaxed half up-do with loose curls to complement her traditional outfit.

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Polished down - The Princess with a polished straight hairstyle and smooth side-swept fringe for a Christmas party at the Anna Freud Centre in London in 2015.

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Side fringe - Middleton with a fun side fringe at ICAP's brokers London office charity event in late 2015.

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Smooth ponytail - A smooth and sleek ponytail for a charity event on mental health in 2015.

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Windy waves - A windswept look at the Fostering Excellence Awards ceremony in London in 2015.

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Half up-do - The Princess opted for a classic half up-do with a side-swept fringe for a charity event in 2015.

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1960s inspired ponytail - The Princess with a 1960s inspired ponytail for the premiere of James Bond movie 'Spectre' in 2015.

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Twisted up-do - Middleton with a twisted up-do.

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Blow-out - The Princess oozes vintage glamour with this blow-out for a day trip to Dundee in 2015.

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Navy fascinator - The Princess wears a navy headpiece with a low bun for the commemoration service at St Paul's Cathedral in 2015.

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Wrapped ponytail - A smooth and high ponytail for an event at the Contemporary Art Gallery in 2015.

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Sleek and straight - Straight and shiny locks with a slight wave. Classic Kate.

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Kate's headgear - The Princess has worn many headpieces and hats in her royal duties.

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Polished side bun - A textured but sleek low side bun for a garden party in Northern Ireland in 2016.

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Classy bun - A low bun and flowery headpiece to match her crisp white tailored outfit.

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Pastel cocktail - The Princess in a pastel-hued headpiece and pale coat for World War I commemorations in 2014 in Mons, Belgium.

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Newsboy cap - A newsboy hat to attend a scout volunteering day in Cumbria in 2013.

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Navy cocktail - An elegant half up-do and navy cocktail headpiece during the Diamond Jubilee in Nottingham in 2012.

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Pillbox - A pillbox headpiece for the St. Patrick's Day Parade in Aldershot in 2012.

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Delicate in lace - A structured up-do to complement her delicate lace outfit for at Royal Ascot in 2017.

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Elegant in black - An elegant black headpiece to visit De Montfort University in Leicester in 2012.

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Howdy Kate - In 2011, the newly married Kate rocks a cowboy-inspired hat to a Calgary Stampede.

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Accent red - Middleton embraces Canadian colours in a white and red outfit for a visit to the Canadian Museum of Civilization in 2011.

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Bold in black - A flamboyant black headpiece and loose curls for Trooping the Colour ceremony in 2011.

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Faux fur hat - A furry hat for a day out in Stockholm's Old Town.

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Bobble hat - A fun bobble hat for a hockey match in Stockholm.

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Wedding tiara -

A 1,000 diamond Cartier tiara and veil on her wedding day!

See also: Extravagant jewelry owned by British royals

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