Thousands of Oprah Winfrey fans are expected in Chicago for a star-studded, double taping of her talk show as it approaches its finale.
The show dubbed "Surprise Oprah! A Farewell Spectacular" starts Tuesday evening at the United Center, just blocks from Winfrey's long-time studios. Winfrey's producers say the guest lineup is a secret, but they promise "the biggest names in movies, music and television."
Tickets were free and distributed to fans through a lottery. The episodes will air May 23 and 24, before Winfrey's final show on May 25.
Executive producer Sheri Salata says Winfrey is "in great spirits, energized and taking in every last bit of these final days."
Winfrey announced in November 2009 that she would end "The Oprah Winfrey Show" this year after 25 years.