Oprah Winfrey is #1 on Forbes ' list of Hollywood's most influential celebrities , followed by Steven Spielberg, Dr. Mehmet Oz, Bono , and Clint Eastwood . 

Oprah is America's tastemaker, turning books into best-sellers, films into must-sees and guests into super stars with a quick focus of her attention.

E-Poll Market Research ranks more than 5,000 celebrities on 46 different personality attributes. It found that 55% of the U.S. population would use the term "influential" to describe Oprah.

To determine who else makes our list of Hollywood's Most Influential Celebrities, likability and awareness metrics were factored in, as well.