LOS ANGELES — Season 1 winner Kelly Clarkson took the stage at the end of American Idol on Thursday night and did something that made everyone cry — including judge Keith Urban.

Clarkson sang “Piece by Piece” in an unbelievably emotional performance, breaking down in tears during the song and prompting most in the audience to get teary, too.

Clarkson was so emotional that she missed a few words of the song.

The song is about her father leaving her and how she will not leave her children.

After the performance, Clarkson, who is pregnant and looking forward the birth of her second child, apologized to host Ryan Seacrest.

“I’m pregnant and I’m nostalgic and I can’t believe it’s the last season, and I’m really sorry, but I just bawled,” she told the crowd.