07/24/2013 10:18 EDT

Kate Middleton Effect: Polka-Dot Dresses Sell Out After Duchess Of Cambridge Introduces Royal Baby

LONDON, UNITED KINGDOM - JULY 23: Catherine, Duchess of Cambridge leaves The Lindo Wing of St Mary's Hospital with her newborn son at St Mary's Hospital on July 23, 2013 in London, England. (Photo by Samir Hussein/WireImage)

As the world gazed for the time on the Duke and Duchess of Cambridge's royal baby on Tuesday, keen-eyed shoppers made their way to their computers, credit cards in hand, and lined up in front of cash registers to get themselves some Kate Middleton-inspired frocks.

Kate's polka-dot Jenny Packham dress (a subtle nod to Princess Diana) caused women to buy polka-dot frocks in droves, so much so that one of the UK's biggest brands sold out of the dresses within hours on Tuesday.

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Photo gallery First Royal Baby Photos See Gallery clothing reported that more than 5,000 of its polka-dot dresses sold online as women hurried to snap up a piece of clothing that would emulate the royal mum.

Other polka-dot items including high-waisted shorts, chiffon skirts, vest tops, bikinis and ballet pumps also saw a boost in sales overnight.

Jenny Packham saw her website crash on Tuesday after Duchess Kate proudly showed off her yummy tummy in the UK designer's dress.

Packham's named even trended on Twitter just minutes after the Duke and Duchess stepped out of the Lindo Wing of St. Mary's Hospital with their baby boy.

The "Kate Effect," as the phenomenon has been lovingly called, has been in full force since Middleton's Alexander McQueen wedding dress sent women into a frenzy, snapping up look-a-like gowns. Since her wedding to Prince William in 2011, Kate's fashion has boosted sales for whichever designer she happens to wear and her maternity style has also caused shoppers to snap up outfits online.

So, as we wait for the official portrait of the young royal family, we can predict that Kate mania won't die down anytime soon.

Kate really does have amazing style: