Police plan to shut down Michigan Avenue between Wacker and Ohio just after 12 a.m. on Monday. It won't reopen until 5 a.m. on Wednesday, September 9.
A spokeswoman says Harpo Productions will pay for police, paramedics, sanitation and other security, a point the mayor emphasized several times Tuesday.
"She's going to pay for all of it. See? You can report that," said Mayor Daley. "Oprah is going to pay for the entire cost. That's number one. It's filming, it's filming, it's open to all ages. She's going to pay for it. Now aren't you excited?"
The taping includes a performance by the Black Eyed Peas.
Admission is free.
The gates at Michigan and Ohio will open at noon on Tuesday, but camping out overnight is not allowed.
Read the press release about the event here.