"No More Tears (Enough is Enough)," a song that Summer recorded with Barbra Streisand in the 1970s, was pre-recorded after the May 22 "Idol" broadcast at the Nokia Theatre L.A. LIVE. Chenoweth later tweeted, "I was so excited and nervous. And proud of my duet partner."

Tony Award winner Jennifer Holliday will also perform on the "Idol" grand finale. The actress, who will reprise her performance as Effie White this summer in The Muny's production of Dreamgirls, tweeted, "HAPPY 2 ANNOUNCE: JENNIFER HOLLIDAY & JESSICA SANCHEZ WILL SING A DUET 4 THE 'AMERICAN IDOL SEASON FINALE'."

Earlier this season on "Idol," Sanchez performed "And I'm Telling You" from Dreamgirls. The singer competes against Phillip Phillips for the title of "American Idol" in the reality singing competition.

Chenoweth won the Tony Award in 1999 for her performance in You're A Good Man, Charlie Brown. She was nominated in 2004 for her performance in Wicked and has also been seen on Broadway in Steel Pier, Epic Proportions, The Apple Tree and Promises, Promises. Visit her page at the Playbill Vault.

Holliday has also been seen on Broadway in Chicago, Grease and Your Arms Too Short to Box With God. For more on her theatrical history, visit the Playbill Vault.

For more information, visit AmericanIdol.com.