She's the world's most stylish mum-to-be.

On Monday, the palace announced the Duchess of Cambridge is expecting her first child with her husband, Prince William. Before the world's most fashionable royal child is born, we take a look at the sartorial selections of Kate Middleton, who topped multiple best-dressed lists including Vanity Fair's International Best-Dressed List of 2012.

The 30-year-old is so influential with her clothing that a retail term has been created after her dubbed, "The Kate Middleton Effect," which basically implies that she drives retail sales like no other celebrity or royalin the world. Take a look at her classic, well-tailored pieces, below.