Nicole Richie led the way this morning as she and Kate Hudson headed to catch a flight out of Heathrow. The girls have been friends for a long time, with Nicole memorably stepping out for Kate's Halloween bash last year. Kate was traveling with her son, Ryder, and boyfriend, Matt Bellamy, leaving London after arriving there two weeks ago. Kate wrapped up her stay abroad by having dinner with Matt and pal Stella McCartney last night, which was a fun end to a trip that included some business. Nicole, though, was flying solo following a fun few days with her husband, Joel Madden, on tour. They met up in Paris to do some shopping together before Nicole joined him on a quick breeze through Ireland, where she discovered the advantages of having the last name Madden.