The Richie-Maddens

They're now a family of four! See how Joel Madden and Nicole Richie dote on daughter Harlow and son Sparrow

BIRTHDAY BUNCH

A few days after throwing Harlow a star-studded bash, the proud parents – and newlyweds! – take their birthday girl and her little brother Sparrow, 16 months, out for a walk in Hollywood on Jan. 11. "Happy Birthday to my little princess," Madden Tweeted. "You make mommy and daddy so proud."