Age: 31
Occupation: Musician, clothing mogul
Simpson got her start as a pop singer and the star of a first-generation reality-TV show, on which she famously expressed confusion about whether tuna was fish. But the star, now pregnant with her first child, has made her fortune in fashion. Her eponymous clothing, shoe and accessories lines are slated to rake in more than a billion dollars this year. In March, Simpson returned to television with a new small-screen persona, as the voice of expertise on NBC's design-competition show Fashion Star.