Demi Lovato duets with her idol Kelly Clarkson at Z100s Jingle Ball in New York City

.Demi Lovato attends Z100's Jingle Ball 2011, presented by Aeropostale at Madison Square Garden on December 9, 2011 in New York City. .....

A dream came true for Demi Lovato at Z100s Jingle Ball concert in New York on Friday.

The Skyscraper singer,19, who energized the crowd by performing some of her hits, All Night Long, Give Your Heart a Break, Unbroken, and Skyscraper, helped put the crowd in the holiday spirit by joining Mr. Know it All singer Kelly Clarkson,29, in a duet of Have Yourself a Merry Little Christmas.

Oh my God..... Oh my God.... Oh my God..... #shaking, she tweeted of performing with Clarkson, who she considers one of her inspirations.

By the end of the performance Demi was in awe of her duet.

I. Just sang. With Kelly. Clarkson. #ahhhhhhh, she wrote.

Clarkson, who went on to perform some of her new and old hits, had nothing but kind words for Lovato.

@ddlovato girl we have got to sing together again! she tweeted. You have such a powerful and beautiful voice! I love your spirit! Thanks for singing with me tonight :)

Prior to their Christmas duet, the two powerhouse singers expressed admiration for one another.

@ddlovato you sang your butt off tonight!! You are so talented and beautiful :) great job girl!! Kelly wrote after a concert on Dec. 8.

@kelly_clarkson YOU are so talented and beautiful!!! Lovato responded. THANK YOU!!! :)

Demi Lovato and Kelly Clarkson werent the only ones to energize the crowd at Madison Square Garden. According to MTV News, so did acts like Kar! min, LMF AO, Pitbull, Foster the People, Mindless Behavior, the Script, David Guetta, Gym Class Heroes and Mother Monster herself Lady Gaga.

Watch Kelly and Demis duet below: