Final episode will be taped on May 17 in Chicago's United Center

CHICAGO - For 25 years, Oprah Winfrey has given the world a window to poets and politicians, A-list actors and musicians, through talk show topics that defined and reflected American culture.

As The Oprah Winfrey Show ends, with 16 episodes left as of May 4, millions of fans around the globe are waiting to see how she will close out the show.

Winfrey's producers plan to hold a star-studded, double taping on May 17 at Chicago's United Center. The shows will air on May 23 and 24.

The show is dubbed Surprise Oprah! A Farewell Spectacular. Winfrey hates surprises, producers say, but she has agreed to this event.

But for fans, questions remain.

Who will be at the United Center that Tuesday night? Who will be beamed in by satellite or deliver a taped farewell message?

Winfrey has a stable of celebrity friends who have appeared repeatedly on her talk show, including John Travolta, Tom Cruise and Katie Holmes, Jennifer Aniston and Chris Rock.

Then there are presidents and world leaders: Bill Clinton; George W. Bush; Nelson Mandela. President Barack Obama and first lady Michelle Obama have already appeared on a special show that aired on Monday.

Winfrey also has other well-respected friends who could be possibilities: Maya Angelou; Sidney Poitier; Barbara Walters.

It has the makings for a major cultural event, said Bill Carroll, an expert on the daytime television market for Katz Television in New York.

"It's going to be the top-of-the-top of anybody who is available to go to Chicago on that day," Carroll said. "It's going to be talked about and talked about and watched and talked about."

Harpo Productions received more than 154,000 ticket requests for seats to the event - the United Center's capacity is about 20,000. There was a lottery for seats.

"For a national, international audience that's a small number," said Marianne Jennings, an Arizona State University professor who has researched the ticket industry for decades.

Tickets for the Chicago taping could be even more coveted than seats for the Super Bowl or World Series, she said.

"It's a once-in-a-lifetime event," Jennings said. "There's something that grips us about that. It's something about being there with the crowd, being there for history."

Winfrey's talk show history is anything but small: 30,000 guests, 4,500 episodes and 283 items named her "favorite things" in the famous annual giveaway.

But there's still a bigger question: What will Winfrey do for the May 25 finale? Harpo isn't talking, nor is the talk show queen.

Experts suggest the Chicago celebrity blowout means that the finale will be in Winfrey's studio for a quieter, more intimate occasion, maybe even without an audience.

"If I were a longtime viewer, I'd want the show to end in a place where I'm most comfortable with her and most familiar," said Janice Peck, author of The Age of Oprah: Cultural Icon for the Neoliberal Era.

Viewers are looking for a heartfelt connection after having daily interaction with Winfrey for 25 years, Peck said.

"The longtime fans are going to feel cheated if she doesn't somehow honor that history," Peck said. "They want to be crying. They want to feel something, some powerful emotional departure."

A model to look to would be Johnny Carson's final episode as host of The Tonight Show in 1992, Carroll said. There were no guests and after his traditional monologue, Carson showed a montage of past shows.

"For the better part of the end of the show he sat there on a stool and just talked directly to people at home," Carroll said. "That had so much class to it."

Associated Press