Pop musician Stevie Wonder and gospel vocalist BeBe Winans performed for 1,500 guests who paid $2,300 each to support and meet Senator Obama (D-Ill.).  Guests included Chris Rock, Whoopi Goldberg, Sidney Poitier, Forest Whitaker, Cindy Crawford, Jimmy Connors, Linda Evans and Dennis Haysbert, according to the Associated Press. Actors Will Smith, Jamie Foxx and Halle Berry were also expected to attend.

Guests were instructed to leave cameras and recording devices at home and the media was barred from the event. Yet despite the media ban, photographers in helicopters buzzing overhead did their best to capture the spectacle of celebrities arriving for the event.

The gala reportedly raised $3 million for the presidential campaign of Sen. Obama. However, there is considerably more speculation surrounding the extent to which Ms Winfrey’s backing might expand Sen. Obama’s political base, especially with respect to African-American and women voters.

“It’s very hard to say,” Sen. Obama told the Chicago Tribune. “I think a presidential race is unique. The job is unique. People who might buy my book because of an appearance on Oprah are obviously going to have a much more serious and sober deliberation when it comes to deciding who the next leader of the free world is.”

A CBS Newspoll found that thirty-one percent of registered voters surveyed believe that most people they know would be more likely to support Sen. Obama’s bid for the White House because of Ms Winfrey’s endorsement. However, 63 percent said the endorsement would not make any difference, while 3 percent said that most people they know would now be less likely to vote for him.

Nevertheless, Ms Winfrey has been called “arguably the world’s most influential woman” by the American Spectator, CNN and Time.com. Her fan base is fiercely loyal owing to her down-to-earth manner and rags-to-riches story. She grew up in rural poverty in Mississippi, first caught the public’s eye in the Steven Spielberg film The Color Purple, and then became a cultural icon when her Chicago-based Oprah Winfrey Show went national in 1986.

Today, her wealth is estimated at $1.5 billion and her media empire includes a women’s television cable network, a film production company, a radio channel, a magazine and a web site that reportedly attracts 68 million page views per year.

She has previously avoided the political arena. Yet following Sen. Obama’s appearance on her show in 2004, following his keynote address at the Democratic National Convention, the two became friends. They later flew together to the Gulf Coast following Hurricane Katrina in 2005 to view the devastation and the displacement of local residents.

“I haven’t been actively engaged before because there hasn’t been anything to be actively engaged in,” said Ms Winfrey. “But I am engaged now to make Barack Obama the next president of the United States.” She is reportedly considering appearing in television ads for Sen. Obama and speaking at public appearances.

While he remains circumspect regarding the political dividends that might result from Ms Winfrey’s endorsement, Sen. Obama acknowledges that her enormous popular appeal could well open doors to audiences he might otherwise not reach.

“Ultimately, they’ve got to be persuaded by me that I’m the right person for the job, but Oprah is somebody who has enormous reach, and that means that I may get a hearing in certain quarters,” he said.