Kelly Clarkson and Carrie Underwood to Return to 'American Idol' For Star-Studded Grand Finale

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For American Idol's three-night grand finale, some familiar faces will be turning to the celebrated stage.

The very first Idol winner, Kelly Clarkson, and season four winner, Carrie Underwood, are set to appear on the last night of the show's epic three-day series finale.

WATCH: 'American Idol' Winners: Where Are They Now?

Fox announced the news on Thursday, revealing that several other alum, including Jordin Sparks, Ruben Studdard, Fantasia, Taylor Hicks and David Cook, will be returning for the star-studded send-off as well.

The original trio of judges, Simon Cowell, Randy Jackson and Paula Abdul, are also set to share some never-before-told stories about the creation of the beloved series and some behind-the-scenes secrets from the first years of the show.

Clarkson made her triumphant return to the Idol stage earlier this season, bringing two of the current judges, Jennifer Lopez and Keith Urban, as well as the in-studio and at-home audiences to tears with a powerhouse performance of her emotional single, "Piece by Piece."

WATCH: Kelly Clarkson Calls Her 'American Idol' Performance 'a Perfect Ending'

The pregnant singer implied that the February appearance would be her last time on the show when she tweeted, "What an emotional night. Thanks @AmericanIdol for such a beautiful beginning & a perfect ending."

Clarkson is quickly approaching her due date, even referencing her pregnancy on-stage last month, but as the original Idol -- she was crowned on season one in 2002 -- it makes sense that we'll see the 33-year-old Texas native in some capacity for the show's massive conclusion after 15 seasons.

WATCH: Kelly Clarkson Brings 'American Idol' Judges to Tears

American Idol's grand finale kicks off April 5 at 8 p.m. ET/PT with the 90-minute retrospective, American Idol: American Dream. April 6 will see the finalists face off live, and it will be the last chance for fans to vote for the next winner. The very last American Idol will be crowned April 7, at the end of the show's two-hour spectacular.

Relive Clarkson's emotional performance of her hit "Piece by Piece," which made Urban openly weep, in the video below.

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