Pippa Middleton, younger sister of the Duchess of Cambridge turns 31 today, September 6th.

The London-based writer was launched into the spotlight when she joined her sister's wedding party for the Royal Wedding in 2011. When she stepped out in a slinky white Sarah Burton for Alexander McQueen bridesmaid dress she became known around the world as "Her Royal Hotness." Since then, we've become enthralled with Pippa's effortless style.

Pippa also made headlines with rumors circulating that she was secretly engaged to her boyfriend Nico Jackson, an announcement that the duo was hoping to keep quiet until this week (so as to avoid overshadowing her sister's news). We were hoping it was true, but turns out the couple are not engaged!

Click through the gallery to see Pippa's style transformation, and wish her a happy 31st!