On the April 13 broadcast the Top 8 performed songs from the movies, and McDonald, 26, from Huntsville, AL, sang "Old Time Rock and Roll."
On April 20 at 8 PM ET, the Top 7 finalists – Casey Abrams, Lauren Alaina, James Durbin, Stefano Langone, Jacob Lusk, Scotty McCreery and Haley Reinhart – will perform songs from the 21st century.
On the April 21 results show, which also begins at 8 PM, TV watchers can expect performances by Season Seven "Idol" winner David Cook, who will perform his latest hit, "The Last Goodbye," and pop sensation Katy Perry, who will perform "E.T."
Among the many "American Idol" finalists and/or winners who have appeared on Broadway are Fantasia, Justin Guarini, Jordin Sparks, Diana DeGarmo, Ace Young, Tamyra Gray, Constantine Maroulis, Frenchie Davis, Clay Aiken and Taylor Hicks.
For more information about "American Idol," visit www.americanidol.com.