Nicole Richie Pictures With Celebrity Friends: Joel Madden, Rachel Bilson, Kate Bosworth and More

Nicole Richie turns 31 today! We're celebrating her big day with a look back at some of her most memorable photos with her best pals. She had the company of one-time BFF Paris Hilton when they filmed The Simple Life, and other buds like Rachel Bilson, Naomi Campbell and Kate Bosworth have been by her side supporting her fashion endeavours. These days she's mostly around her husband, Joel Madden, his twin brother Benji, and her too-cute kids Harlow and Sparrow. She's one of the best-liked ladies in Hollywood, so celebrate Nicole's big day with a look at her and her friends. Happy birthday, Nicole!