Oprah Winfrey

"I am not here to tell you what to think, I'm here to ask you to think," Winfrey told the cheering crowd, some of whom screamed they wanted her as vice president. She urged voters to back Obama's "new vision" for the United States.
The Iowa speech kicked off a three-state event that was to continue Sunday with the signature rally in Columbus, South Carolina, a state where half the Democratic electorate, like Obama and Winfrey, is African-American.
Obama's campaign had to change the venue for Sunday's appearance from an 18,000-seat basketball arena to an 80,000-seat football stadium to accommodate the vast crowds expected.
Winfrey, viewed as one of the most influential entertainers in the world, is said to be the second-most admired woman in the United States -- just behind former first lady Hillary Clinton, Obama's main Democratic challenger, according to a recent Gallup Poll.
Her legendary book club on her afternoon television chat show has transformed unknown authors into best sellers.
Now Obama hopes her millions of mainly female disciples will help him outpace Hillary Clinton, the first woman with a realistic chance of winning the White House.