Demi Lovato might be devastated that her ex-boyfriend has moved on to a serious relationship with Ashley Greene.
But if this is the case, the young singer is doing a great job at hiding it.
Lovato took to the stage with Joe and his brothers in Mexico City Sunday night. She and her former lover even sang a duet together, entertaining fans with a rendition of "Wouldn't Change A Thing," the same single they performed on American Idol in March.
Check it out NOW and click on the following photos to enlarge pics from the concert: