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The fashion frenzy has continued, despite Kate Middleton's 4-and-a-half month baby belly. The stylish mom-to-be has still been making waves in the fashion world, the clothes she wears instantly selling out in stores.

For her first official appearance of the year in London, Middleton chose a MaxMara Studio wrap dress with a gold ring and necklace.

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The $525 wrap dress, from the 2011 collection, was reportedly bought by the duchess for half price. Her Asprey London diamond pendant necklace costs $3,800.

"There really is a Kate effect…whether she's wearing J-Brand jeans or her Zara cape that she wore just a few weeks ago within minutes everything that she wears sells out," said stylist Jamie Krell.

The dress has become a fashion obsession, appearing all over the Internet on blogs and Pinterest. If you like the dress, you won't be able to get it, as it's sold out in stores and online.

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Although you can't find the dress in stores, other retailers have similar wrap dress styles that can help you copy the look.

Another iconic duchess dress, the navy blue dress worn for her engagement announcement, is now being carried in stores. The Issa dress has just been re-issued in maternity form but can also be worn after pregnancy. The dress is being sold at U.K. store Blossom Mother and Child for $825.