Watch Kelly Clarkson Amazingly Sing 'Since U Been Gone' Backwards

Kelly Clarkson on 'The Tonight Show Starring Jimmy Fallon'

Kelly Clarkson proves she has some serious singing chops.

Kelly Clarkson proved her serious singing chops on Tuesday, when she appeared on The Tonight Show Starring Jimmy Fallon, and had some fun with her 2004 hit, "Since U Been Gone."

It's no secret Fallon is a fan of the song, covering the jam during a memorable Lip Sync Battle. And Fallon could hardly control himself on Tuesday, as he challenged Clarkson to sing the tune backwards.

Thankfully, she was more than up to the challenge! Check out her amazing rendition.

The 35-year-old singer also told a hilarious story backstage, recounting getting food poisoning in Germany. In "Tales From Tour," Clarkson recalled having to go to the bathroom so urgently that she excused herself in the middle of a performance, leaving her band to think she had quit mid-set.

"And the band just kept jamming, like, vamping, and so they kind of freaked out, because they were like, 'What do we do? Like, what song do we start playing?'" she shared. "Because we had a set list, and so they picked a song not on the set list, and it's a song called 'How I Feel.' And the first line of 'How I Feel' -- because, by the way, I come back onstage after every orifice of my body had become violated -- and I just came back onstage just, like, pretending nothing happened. And the first line of the song -- I kid you not -- is, 'Looks like I made a mess again.'"

"I was like, 'No ...'" Clarkson said with a laugh. "Then I just lied and told the audience, 'Oh, sorry, I had to pee.' Because it sounded more ladylike instead of, 'Oh God, everything is coming out of everywhere. I want to die.'"

ET recently spoke to Clarkson about her new album, Meaning of Life, when she opened up about finding her perfect match in her husband, Brandon Blackstock.

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