Clarkson returned to the show that made her a star and performed her song called "Piece by Piece," a heartstring-tugging track that appears on the album of the same name.
"I'm pregnant, and it's nostalgic, and I can't believe it's the last season. And, yeah, I'm really sorry I just bawled. I'm actually quite proud that I made it that far," she told AI host Ryan Seacrest, according to USA Today.
"It's just a touching song for me 'cause I wrote it about my little girl when I was pregnant. Now I'm pregnant with my little boy, which I hope comes out very soon."
But it wasn't just her being pregnant that caused her to choke up mid-performance. USA Today also reports that the tender song with a tough message is directed at her father, who she says abandoned her family when she was 6 years old. Additionally, the lyrics are a tribute to Brandon Blackstock, Clarkson's husband, and who she clearly sees as a wonderful father to their children.
"He never walks away / He never asks for money / He takes care of me / He loves me / Piece by piece / He restored my faith / That a man can be kind / And a father could stay."
And Clarkson wasn't the only one who got emotional. American Idol judge and country singer Keith Urban also got a little teary-eyed during the performance.
Check out the video above to see Clarkson's dynamic performance as well as watch her power persevere through the intensely personal tune.
Let's just say that the standing ovation at the end is well-deserved.