Brilliant Bridesmaid! 

PHOTOS: Kate's Wedding Vs. Diana's

It was Kate Middleton's big day, but her baby sis almost showed her up. 

VIDEO: Watch William and Kate kiss twice

Wearing a emerald green dress, Pippa, 27, arrived at Buckingham Palace Friday night for a wedding reception thrown by Prince Charles in honor of Prince William and Kate's wedding earlier that day.

PHOTOS: Highlights of the royal wedding

At the lavish party, 300 lucky guests -- including Middleton's parents -- enjoyed  dinner and dancing. 

Get more Us! Follow us on Twitter, Friend us on Facebook, Subscribe to Us Weekly