Marc Malkin

Andrew MacPherson

American Idol wants some freedom.

The big surprise guest performer during the American Idol finale tomorrow night will be “Freedom” hit-maker George Michael, a source has exclusively revealed.

Earlier this week, producer Nigel Lythgoe refused to reveal who the artist would be, only saying that the “biggest star in the world” was coming to Idol.

The appearance will time in nicely for the former Wham! frontman, who starts a 20-city tour on June 17 in San Diego in support of his recently released two-disc CD, Twenty-Five.

A rep for Idol would not confirm Michael’s appearance, while a rep for the singer could not be immediately reached.

In addition, David Cook and David Archuleta may perform Michael hits during the two-hour finale that will also include Carrie Underwood performing her new single, “Last Name.” Producers may still be making last-minute plans with additional singers.