Kate Middleton’s world-renowned style evolution predates the royal blue Issa dress she wore for her engagement announcement in 2010. But the dress—and frenzied reaction to it worldwide—certainly solidified her as a style icon, if not a royal one.

“She is always very poised, elegant and stunningly put together,” says Nicolette Lang-Andersen, a Vancouver-based fashion and wardrobe stylist (and London expat). “And it’s been interesting to watch her style changes over the years, from when she first started dating Will, through to her biggest role yet as a royal mother.”

Kate Middleton style evolution: The early years
It’s hard to think back to the days before every best-dressed list (in Britain and across the globe) wasn’t rounded out with a member of the Royal family. But even in her early twenties, Kate Middleton was a style icon— only with fewer pairs of eyes analyzing her every outfit.

“Kate has consistently maintained a very natural, unfussy look, a kind of private –school, down-to-earth country girl look, whether it was jeans and a tailored blazer or a simple wrap dress,” says Lang-Andersen on those early days of an international style icon in the making. “She was casual but put together, and it was always her confidence and elegance that made her stand out from the crowd.”

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Remember the see-through dress she wore to a charity fashion show in 2002? “She looked really demure and also charmed the pants off Prince Charming,” she says about the event that’s widely credited as the Royal couple’s meet-cute. “It worked.”

Kate Middleton style evolution: The fashionable Duchess

The brilliance of Kate Middleton’s style is her ability to align her youthful personality with Royal dressing requirements for a perfectly poised yet relatable look that’s entirely her own. “I do think she’s added her own sense of style to the face of this whole British family,” says Lang-Andersen.

And that’s no easy task, especially for a newcomer. “From my research on everyone else in the Royal family, the look is mostly knee-length dresses and skirts, a conservative V-neck or scoop neck, often closed-toe two-inch heels at most,” she says, citing minimal jewelry with stud earrings and A-line dresses with three-quarter-length sleeves as typical wardrobe staples. Kate’s series of chic hats and fascinators—by Philip Treacy, Jane Corbett and Sylvia Fletcher—have amped up the playfulness of the Royal uniform. “They definitely added a little more sex appeal into her outfits.”

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More of Kate Middleton’s style evolution on the next page…

katemiddleton-page-two.jpgShe grew into her own style, having spent more time in the public eye as Will’s girlfriend and eventually, his betrothed. “Over the years, the quality and structure of the clothing in her wardrobe has certainly changed—it used to be flimsy, more shapeless items,” says Lang-Andersen.

“It’s now become a very sleek, tailored, timeless look. And I think that’s got to do with the role that she has now—and obviously she has a nice collection of designer pieces.” She lists off British labels like Jenny Packham, Alexander McQueen and L.K. Bennett, designers who have become closely associated with the Duchess’ look these days.

Kate Middleton style evolution: The Royal mom

Any fears that Kate would abdicate her style icon status upon becoming a mother were squashed the moment she emerged from St. Mary’s Hospital in London sporting a delicate polka dot baby blue Jenny Packham dress, baby prince in her arms. But her fabulous post-partum style should come as no surprise. “She’s still young,” explains Lang-Andersen. “I think she will still continue to dress the way she has been dressing.” (Fascinators included).

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Times have also changed since Princess Diana stood on those very steps cradling baby Will in a similarly polka-dotted dress. “She dressed more conservatively,” Lang-Andersen says about the Princess of Wales’ style. “At that time of Princess Diana, the trend for length of skirts was mid-shin, which instantly makes someone look a little bit older, and that’s not in fashion now.”

Kate, it seems, is all about making up her own style rules anyway. “She’s paving the way and she’s not shy to wear something that’s a little but louder.” And the fact that she’s snapped back into her pre-baby figure pretty quickly helps. “She’s still really young and has a young, down to earth personality,” says Lang-Andersen. “So I think she’ll keep conveying that through her clothing for sure.”

Read more:
Kate Middleton’s top fashion moments

10 reasons we love Kate Middleton
Kate Middleton maternity style: 8 reasons why we love her look

Kate Middleton style: Must-have accessories