Kelly Clarkson and Carrie Underwood will come home for 'Idol' series finale

After 15 years, American Idol will say goodbye with a three-night grand finale on April 5, 6 and 7. The first night will be a 90-minute retrospective with former contestants and judges. The second night will feature a final round of competitive singing. And on the third night, former Idols Kelly Clarkson and Carrie Underwood will take the stage that made them stars to perform for the last time on Idol.

FOX promises the two-part final will be "filled with surprise appearances and star-studded performances." 

That means a whole lot of former contestants, will be stopping by, including -- deep breath -- Ruben Studdard, Fantasia, Taylor Hicks, Jordin Sparks, David Cook, Kris Allen, Lee DeWyze, Scotty McCreery, Candice Glover, Caleb Johnson, Nick Fradiani, Ace Young, Allison Iraheta, Amber Holcomb, Blake Lewis, Bo Bice, Brandon Rogers, Bucky Covington, Carly Smithson, Casey James, Chris Daughtry, Clark Beckham, Clay Aiken, Colton Dixon, Constantine Maroulis, Danny Gokey, Diana DeGarmo, Elliott Yamin, George Huff, James Durbin, Jessica Sanchez, Josh Gracin, Joshua Ledet, Justin Guarini, Katharine McPhee, Kellie Pickler, Kimberley Locke, Kree Harrison, LaToya London, Lauren Alaina, Melinda Doolittle, Pia Toscano, Sanjaya, Skylar Laine, Tamyra Gray and more.

American Idol will air live from the Dolby Theatre in California on all three nights at 8 P.M.

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