Nicole Richie turns 31 today! It's been an eventful year for her. In the last month alone, Nicole launched her Macy's line, hit up a star-studded wedding in Cabo San Lucas, and debuted her first fragrance. A busy schedule hasn't prevented Nicole from running with a fabulous group of friends, though. Over the years, she's kept the company of friends like Jessica Alba, Jennifer Lopez, and the Kardashians. Click through to see them all — and happy birthday Nicole!