The third- and second-to-last installments of The Oprah Winfrey Show will tape at Chicago’s United Center on May 17 to accommodate “the biggest names in movie, music and TV,” Harpo Prods. announced today. Even Oprah Winfrey doesn’t know who will attend “Surprise Oprah! A Farewell Spectacular” that’s been in the works for weeks at Harpo.

“As most of our viewers know, being surprised is not one of Oprah’s favorite things,” said Sheri Salata, executive producer, in a statement. “In the spirit of our farewell season, she is making a rare exception and we intend to make the most of the opportunity. It will be something to see!”

The two-parter will air May 23 and May 24. The final episode of The Oprah Winfrey Show will air May 25.