COLUMBIA, South Carolina (CNN) -- Williams-Brice Stadium in Columbia, usually the home of the University of South Carolina football team, is getting ready for Oprah Winfrey and Sen. Barack Obama.
Oprah Winfrey appears with Sen. Barack Obama and his wife, Michelle, at a September fundraiser in California.
One of the goal posts already has been dismantled. The marquee outside ordinarily flashes "Go Gamecocks," but this week it had something different to promote: "Rally with Senator Barack Obama and Oprah Winfrey," it reads. "Free and Open to the Public."
The talk-show host will hit the campaign trail this weekend with the Democratic presidential candidate and his wife, Michelle, making two stops Saturday in Iowa and then traveling to South Carolina and New Hampshire on Sunday.
The appearances come a few weeks before the crucial January 3 Iowa caucus.
This weekend will put the notion of celebrity endorsements to the test. Winfrey raised nearly $3 million for the senator from Illinois at a glitzy California fundraiser in September, but whether she can bring new people into the political fold is a different story.
"Oprah is not going to change people's minds on her own, but Oprah makes Obama salient," said Winthrop University political scientist Scott Huffmon, adding that the media attention will be the biggest boon for Obama.
"If he pulls off an upset in Iowa, suddenly he is at the forefront of everyone's mind and he has the momentum. And he can use it to springboard him through in South Carolina."
The events in Iowa also are valuable organizing and recruiting tools for Obama. Tickets were first given to precinct captains, who were told to take as many as they wanted and give them out, according to CNN's Candy Crowley.
Then those who wanted tickets had to go to one of Obama's offices and volunteer for four hours or attend a caucus-organizing seminar. After those people, others seeking tickets needed to go to an office and provide information.
The rally appears to be generating the most buzz in South Carolina, where "overwhelming demand" for free tickets forced the campaign to move the Sunday event from an 18,000-seat arena to the 80,000-seat football stadium.
Inez Tenenbaum, who co-chairs Obama's campaign in South Carolina, announced the move outside the candidate's Columbia headquarters Thursday. People were camping out there to get free tickets, she said.
"This event far exceeded our expectations," said Obama spokesman Kevin Griffis, who said the campaign had to negotiate with the University of South Carolina to get the stadium.
The campaign does not expect to fill the stadium -- that job is usually left for football coach Steve Spurrier and his Gamecocks. But privately, Obama aides said they have high expectations for the event and are confident the rally will attract tens of the thousands of supporters.
"It may be the biggest crowd for a political candidate in South Carolina's history," Jack Bass, a College of Charleston professor, told The State newspaper on Thursday.
But for all the hype, will those Winfrey and/or Obama fans be registered voters? His campaign here, with an unprecedented grass-roots organization, has toiled to translate the senator's celebrity into voters by targeting potential supporters.
The event ticket has a "voter pledge," asking attendees for names, addresses and phone numbers and also to check a box saying, "I support Barack Obama and will vote for him in the S.C. Democratic primary on January 26."
The campaign has distributed fliers with a similar pledge at events throughout the state.
Some political observers said Winfrey's support could help Obama draw female voters from front-runner Clinton.
"Hillary Clinton simply seems to be the women's candidate regardless of race," said Keating Holland, CNN's polling director.
"I think that's what Obama may really be trying to reach is women -- not white women or black women or any particular race, just women in general.
"Married women, women with children -- those are the ones who tend to turn out and vote," Holland said. "Those are the ones that have more at stake, so they're more willing and eager to go out and vote in primaries and the general election. That tends to be the Oprah audience."
Clinton's campaign said she is a big fan of Winfrey's and thinks it's great for candidates to bring in surrogates but ultimately voters will pick candidates based on their experiences, strengths, records and abilities to do the job. E-mail to a friend
CNN's Candy Crowley contributed to this report.