Some celebs actually are doctors; they don't just play one on TV. Keep clicking to see which stars have earned or are working on their M.D., Ph.D. or Ed.D. (and we're not counting honorary degrees). Here, comedian Bill Cosby, who earned an Ed.D. from the University of Massachusetts Amherst, speaks at the 20th anniversary of the Rev. Al Sharpton's organization the National Action Network on April 6, 2011, in New York City.