This April, William and Kate will celebrate their 10th wedding anniversary, marking the occasion when Catherine Middleton became the Duchess of Cambridge and began her reign as royal fashion queen.

Now a mum of three, Kate’s style has changed considerably over the years, as documented by fashion writer Bethan Holt in her new book The Duchess Of Cambridge: A Decade Of Modern Royal Style.

Here’s a look back at 10 key looks from the past decade, and how Kate’s personal style has evolved…

2011: Bridal bliss

Kate Middleton arrives at Westminster Abbey, London, before her marriage to Prince William.
(Gareth Fuller/PA)ha

"Kate’s wedding dress was such a clever blend of the personal and historical," says Holt, of the gown designed by Sarah Burton for Alexander McQueen.

"Those long lace sleeves felt very classic and demure, perhaps a nod to Grace Kelly, but then the subtle bustle detail elevated it into something more grand and stately, befitting a future Queen. It was brilliant that she supported a British label which had been quite avant-garde, too."

2012: Pretty in pink

The Duchess of Cambridge attends a garden party at Buckingham Palace, London.
(Carl Court/PA)

The Duchess chose an Emilia Wickstead dress and Jane Corbett hat for a royal garden party. "This was such a pretty look for Kate’s first Buckingham Palace garden party," Holt says. "Although she knew all eyes would be on her, she nevertheless chose to recycle a dress worn earlier in the year, which showed that she was conscious of not upstaging more senior royals, but her new hat really rose to the occasion."

2013: Spot the difference

The Duchess of Cambridge arrives for her visit to Warner Bros studios in Leavesden, Herts where the popular Harry Potter movies were produced.
(Steve Parsons/PA)

"When Kate chose a Topshop maternity dress, it was a very relatable moment for women around the world," says Holt. "Thousands chose to buy into her look, creating a huge uplift in sales for the high street retailer."

2014: Bold and beautiful

The Duke and Duchess leave the Sydney Opera House following a reception hosted by the Governor and Premier of New South Wales during the tenth day of their official tour to New Zealand and Australia
(Anthony Devlin/PA)

Kate donned a bright yellow Roksanda frock for a visit to the Sydney Opera House during the official tour of New Zealand and Australia.

Holt says: "This was such a bold fashion moment from the Duchess. She had been doing diplomatic dressing for a while by this point, but Australia’s national colour, yellow, is perhaps not the easiest to wear. She could have incorporated it in an understated way, but I love that she just went for it here."

2015: Full bloom

The Duchess of Cambridge arriving for the 100 Women in Hedge Funds Gala Dinner in aid of The Art Room, at the Victoria and Albert Museum in London
(Chris Jackson/PA)

"With its over-blown floral print and full skirt, this gown proved to be a divisive look," Holt says of the colourful Erdem gown seen at the 100 Women in Hedge Funds Gala Dinner. "Some people loved how different it was to anything Kate had worn before, others found it too fussy.

"It’s interesting that the Duchess chose to depart from her previous eveningwear norm of flowing, classically elegant gowns at a dinner full of professional women – she was taking a risk and creating a talking point."

2016: Feeling blue

The Duke and Duchess of Cambridge during a visit to the Taj Mahal in India during day seven of the Royal tour to India and Bhutan.
(Dominic Lipinski/PA)

"There was so much pressure on Kate and William when they visited the Taj Mahal, as it had been the site of one of Princess Diana’s most symbolic photo opportunities," Holt says.

While Diana wore a bright pink jacket, Kate chose "a calmer, more peaceful shade of blue in the form of an embroidered shift dress by Indian designer Naeem Khan. It was a great tribute to local talent and helped the Duchess to make the moment her own," says Holt.

2017: Lady in red

The Duchess of Cambridge attends The Queen's Birthday Party in Germany at the British Ambassadorial Residence.
(Chris Jackson/PA)

"It’s no surprise that Kate was compared to the dancing lady emoji when she wore this dress on tour to Germany," says Holt. "This was a complete departure from her usual sleek silhouettes and the off-shoulder cut was quite daring, but it was still by one of her most trusted labels, Alexander McQueen."

2018: Top coat

The Duchess of Cambridge arriving at the Karolinska Institute in Stockholm to hear about Sweden's approach to managing mental health challenges.
(Dominic Lipinski/PA)

Catherine Walker, the brand that designed this coat, has been popular with royals for many years.

"It was the label which Princess Diana wore the most consistently all through her public life, and now it furnishes the Duchess of Cambridge with bespoke pieces for big moments, like this tour to Sweden," Holt explains.

"The red and white houndstooth print is eye-catching and classic, but I think there was a diplomatic message to it too as the following day, Kate and William arrived in Norway, which has a red, white and blue flag."

2019: Modern moment

The Duchess of Cambridge during a visit to the Henry Fawcett Children's Centre in Kennington, London
(Arthur Edwards/PA)

"This was a major fashion moment for Kate – she looked so polished, modern and elegant wearing a Gucci pussy-bow blouse, which was at once classic and of-the-moment," says Holt. "She had also only recently started wearing trousers, and she really owned that masculine/feminine look here."

2020: Going green

The Duchess of Cambridge in Dublin during her three day visit to the Republic of Ireland
(Phil Noble/PA)

"Kate’s Ireland tour was a masterclass in making diplomatic dressing exciting," says Holt. "She kicked things off with this dress by Alessandra Rich – one of her new favourite discoveries – in a shade of green which I think could be labelled challenging. But it was a powerful gesture to a shade synonymous with Ireland, whilst still feeling fun and ladylike."

The Duchess of Cambridge: A Decade of Royal Modern Style by Bethan Holt
(Ryland Peters & Small/Shutterstock/PA)

The Duchess Of Cambridge: A Decade Of Modern Royal Style by Bethan Holt, is published by Ryland Peters & Small. Available now.