The Duchess of Cambridge Kate Middleton who is expecting her first child with Prince William, turned 31 today and celebrated with a low profile party.

The Princess who is entering her second trimester is said to have spent her birthday "privately," St. James' Palace said.

Middleton is thought to have spent her special day with her husband at their home in north Wales, according to UK's The Mirror. 

The Princess was born to parents Michael and Carole Middleton at the Royal Berkshire Hospital on January 9, 1982. She met Prince William at the University of St. Andrews, Fife and married him at a lavish ceremony on April 29, 2011.

Since then, she has become a fahion icon, gracefully showcasing elegant dresses, flattering accesories and an astounding taste for shoes. She has reportedly helped trigger sales of designer clothes and has been an inspiration for many women who look up to her unique style.

Click on the Slideshow for a glimpse of the Princess' Fashion Style!