Demi Lovato Surprises Jessie J Fans By Filling In For Ariana Grande on "Bang Bang." How Did She Do?

Let's be real with ourselves for a minute— "Bang Bang" is probably the greatest pop tracks of the year (if not of all time). So the energy was already running high when Jessie J belted those first high notes during a concert in San Jose last night. But the singer took things to a different level when she brought out Demi Lovato to take Ariana Grande's verse on the hit song.

The crowd predictably went crazy when Jessie J brought out her special guest, and Demi gave Ariana a run for her money with pitch-perfect precision. Sadly, neither diva took on Nicki Minaj's rapid fire rap verse. But that's probably for the best because our heads would have probably exploded from sheer pop awesomeness. Watch the video above taken by a lucky fan!

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