Applegate is a fan favorite outside The Late Show with David Letterman studio in New York City. Plus: Harrison & Calista, Nicole & Joel, Mary-Kate Olsen and more

DOING THEIR PART

Glamming up for a good cause, expectant mom Nicole Richie and boyfriend Joel Madden cohost a fund-raiser Monday through their Richie-Madden Children's Foundation with Sony Cierge for UNICEF's Tap Project, which helps provide clean and accessible water to children around the world, at Hollywood hotspot MyHouse.