Kelly Clarkson does killer covers -- it's part of why she nabbed the first ever 'American Idol' title -- and she's at it again, this time with her rendition of No Doubt's hit 'Don't Speak.'

Clarkson encourages fans to tweet suggestions for her covers before each of her concerts, and at a recent stop in Phoenix, Ariz., one asked for the trademark track by the California-based, Gwen Stefani-fronted rock outfit. This delighted Clarkson, who told the crowd, "Thank you so much for requesting this song! This is one of my favorite No Doubt songs. I hope you enjoy it."

Flanked by only an acoustic guitar and a spotlight, Clarkson sat down and poured her heart into the heartbreaking tune, giving it the grit and edge that few voices other than the 'Duets' mentoring diva can provide. Clarkson's hallmark songs are breakup anthems, but this song of crushing defeat at the hands of a dismissive and distant lover showcases the 'Stronger' singer's vulnerability.

Stefani may want to watch her back. Clarkson is on a roll lately! Her single 'Stronger' recently became the biggest seller in 'American Idol' alum history, and she's tackled the likes of Katy Perry's 'Wide Awake' and Britney Spears' 'Everytime' live. It's an unspoken but understood notion that Clarkson's vocals blow most of the original versions of each song out of the water, but she gives the hard rocking nature of 'Don't Speak' a softer, more tragic (kingdom!) feel by taking out a lot of the background noise. Job well done, Kel!

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