Kelly Clarkson Gives 'American Idol' Its First 'Can't Miss' Moment Of The Final Season (Video)

It's hard to imagine what AMERICAN IDOL would have looked like over the years if it hadn't been for season one winner Kelly Clarkson. Like SURVIVOR's Richard Hatch, she defined the show for its entire run and while the Idol has created some big stars, none of them have the singing range or writing skills of Clarkson.

Just seven weeks away from giving birth to her second child, Clarkson appeared on IDOL on Thursday as a guest judge. Her quirky, heartfelt and on-topic comments were a welcome change for what usually passes for judge's feedback on the show this season. But what stopped the show was her emotional performance of "Piece By Piece," the title track from Clarkson's 2015 album.

While Clarkson's hits have tended to be collaborations with hit machines like Max Martin, some of her best tunes have been personal, intimate songs such as the heartbreaking "Because Of You," in which she talks about her relationship with her mother. "Piece By Piece" was written by Clarkson just after her daughter was born and in it she talks about finding love with a man who won't leave her and their child the way her father left her.

In a 2015 interview with Glamour, Clarkson talked about the song and why she considers in a positive tune, even though it's so emotional that she has trouble getting through it every time she sings it:

It wasn’t a hard song to write, but we have been rehearsing it, and I have yet to get through it—emotionally, I don’t mean vocally. I haven’t gone through it yet once, so that will prove to be interesting. It’s not even sad tears; it’s just such a beautiful thing that I have found. It’s completely magical because there’s a little part of me that didn’t even know that it existed. I knew that this kind of love existed and that other people found it, but it’s such a breathtaking moment. I’m going to just have to deaden myself and not listen to the words that I’m singing. I’m an emotional singer anyway, so it’s easy for me to get lost in any story that I’m the vessel for at that moment.

And true to Clarkson's warning, she wasn't able to get through the song without crying when she sang the tune Thursday. But watching the tender, raw performance below is a reminder of the depth of Clarkson's talent. It's also a reminder that Fox and AMERICAN IDOL couldn't have picked a better person to win the first season of the show. It's not unlike conducting a Battle of the Bands in 1962 and have The Beatles show up as one of the contestants.