Kelly Clarkson Jams at Z100 Jingle Ball!

Kelly Clarkson belts out some high notes at the Z100 Jingle Ball, held on Friday (December 9) at Madison Square Garden in New York City.

The 29-year-old entertainer hit the stage and sang “Since U Been Gone,” “Stronger,” “Mr. Know It All,” and “My Life Would Suck Without You.” Kelly also sang “Have Yourself A Merry Little Christmas” as a duet with Demi Lovato!

PHOTOS: Check out the latest pics of Kelly Clarkson

“@ddlovato girl we have got to sing together again! You have such a powerful and beautiful voice! I love your spirit” Kelly tweeted at Demi after jamming together!

Check out this video of Kelly and Demi singing “Have Yourself A Merry Little Christmas”…

20+ pictures inside of Kelly Clarkson performing at Z100 Jingle Ball…