Catherine Zeta-Jones for T-Mobile. Angelina Jolie for St. John. Gwyneth Paltrow for Estée Lauder. Nicole Kidman for Chanel. A-listers, who once upon a time avoided advertising like the plague (except, of course, their movie trailers), are pushing products in unprecedented numbers—and for good reason. These celebs, many of whom average $15 million to $20 million for movie work requiring months of their time, are cashing in on ad campaigns that can pay as much as $3 million for as little as a day’s work.