FOR SOME, DEC. 1 WAS JUST another day. For celebs like Wilmer Valderrama, Richard Gere and Demi Moore, it was an opportunity to mark World AIDS Day by wearing T-shirts designed to help break down the fear and stigma that surround the disease. "You're immediately ostracized in so many communities around the world today if you're known to be HIV positive," says designer Kenneth Cole, who put together a public-awareness campaign that included the T-shirts in addition to newspaper and magazine ads, billboards and radio spots featuring the voices of stars, doctors and advocates. First organized by the World Health Organization in 1988, World AIDS Day was started with the hope that "on [this day] people will take a moment and realize that somehow this disease affects all of us in one way or another," explains Jessica Alba, who appears in the print ads.

In New York City's Bryant Park the designer has also erected a temporary building to house a gallery of plaster footprints made by the celeb participants when they posed for photographs over the course of a year. "It's a great message of solidarity," says Mena Suvari, who recorded a radio public-service announcement. "I hope that doing something as simple as wearing this T-shirt will make people think about the stigma still associated with AIDS."