Demi Lovato Rocks Out at the Greek Theatre with Nick Jonas and Madison De La Garza (Video)

Demi Lovato gives Nick Jonas a high five during her concert at the Greek Theatre in Los Angeles on Wednesday evening.

The 19-year-old rocked the stage singing her hits like “Give Your Heart a Break,” “Get Back,” and “Skyscraper” as well as fan favorites like “Got Dynamite,” “Unbroken,” and “Fix A Heart.” About halfway through the show, Demi invited a special guest on stage – none other than Nick Jonas.

The duo chatted a little bit and then went on to perform “Catch Me” and “Don’t Forget” together. Demi also performed “Together” alongside her little sister Madison De La Garza.

Another highlight of the show as Demi’s cover of Lady Antebellum’s “American Honey.” Demi proved she can definitely take on any genre of music. She went on to close out the show with an encore of “Unbroken” and “Give Your Heart a Break.”

Click inside for pics & video from Demi’s show and be sure to catch her hosting the 2012 Teen Choice Awards this weekend!