Oprah joins Obama on bus tour

Oprah Winfrey is confirmed to stump with Barack Obama in Iowa, New Hampshire and South Carolina, the Obama campaign has announced.

While experts may be divided on the "Oprah Factor," the Obama camp appears positive about the star's appeal.

Oprah is known for her Midas Touch in the world of entertainment, and may be the biggest star to campaign actively for a presidential campaign since Frank Sinatra helped John F. Kennedy, and then, switching parties, aided Ronald Reagan in winning office.

Over the decades, Oprah has gained a loyal following who trust her judgment on things like books and films, but this is her first venture into the world of politics.