Duchess Catherine and Prince George [Photo/Agencies]

Trend watch: Catherine and her hats

Highlights of Shanghai Fashion Week F/W 2014

The 32-year-old royal's stunning monochrome patterned dress has flown off the shelves following her high-profile play date with Prince George in New Zealand.

The simple yet stylish 'Paulina' dress, which Catherine sported at a Plunkett's Parent's Group event at Government House in Wellington, is priced at $237 on sale at ToryBurch.com.

However, according to E! Online, it has proved so popular that the item is now out of stock, with women around the world attempting to recreate the duchess' chic look.

The covetable piece has also sold out at Net-a-Porter, Nordstrom.com and Bloomingdales.com.

Meanwhile, baby George is fast becoming a style icon in his own right. The cute Rachel Riley smocked dungarees with a boat design on the front which the eight-month-old tot wore to the event are expected to follow suit.

While the eight-month-old tot's adorable outfit, retailing at $125, has yet to sell out online, some of the most popular infant sizes are already out of stock.

Stockists of the novelty kangaroo backpack the Duke of Cambridge was seen carrying on Monday in Sydney, Australia, also reported the item had sold out just hours after the family's airport appearance.