As American Idol’s final season approaches its end, plans for a grand finale episode are coming together. Of course, it wouldn’t be right without Carrie Underwood or Kelly Clarkson.

Underwood won the competition in 2005 and went on to find massive stardom, as did Clarkson, who was crowned the first-ever Idol in 2002.

The ladies, both now Grammy winners, have officially been booked to appear on the two-night finale running April 6-7, alongside a host of other finalists from the past 15 seasons. Clarkson has already guested once this season, working with contestants and bringing an emotional performance of her song “Piece by Piece,” written about her strained relationship with her father. Her compelling delivery and tearful break brought fans to their feet and judge Keith Urban to tears.

“Separate to her incredible gift as a singer, and the song and the performance, the humanity in that moment was just … you never see that, let alone on television. I was so grateful to be there to witness it,” he said afterward.

Clarkson said the entire experience was emotional for her, being back on the Idol stage and singing such a personal song. She was adorably embarrassed about the breakdown and poked fun at herself on Ellen, calling it an “emotional slip-n-slide from Hell.”

“We were rehearsing that day and I just couldn’t get through it. My 1-year-old is running around the same hallway as I was at 19,” she explained. “[Brandon is] a great husband and a great father. And he was there, my little girl was there, my little boy was, like, turning circles in my stomach. It was nostalgic. It was the last time I was going to be on Idol and it’s ending. I was screwed from the get-go.”

Underwood has not yet appeared on the final season of Idol, as she’s had a lot going on. She recently earned her 23rd No. 1 with “Heartbeat” and has been performing on her Storyteller Tour, which has sold out every date thus far. When she’s not on stage, she’s busy chasing around a 1-year-old, who apparently won’t even let her use the bathroom in peace.

Clarkson is taking a break from touring during her difficult second pregnancy, but she recently announced she’s releasing a children’s book inspired by her daughter River Rose. She also joined Kelly Rowland, Missy Elliott, Janelle Monae, Zendaya, Lea Michele, and other female artists to record an anthem of female empowerment, written by Dianne Warren, in a partnership with First Lady Michelle Obama.

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