The former couple and friends first reunited earlier this year after winning charity song at the 2011 Do Something Awards.
Later in the show, Demi took the stage with Chord Overstreet to present Best Collaboration.
Demi, wearing Mandalay, tweeted after the event, “Shoes are off, going back home.. That was fun. #VMAs”
FYI: Joe is wearing DSquared2.
20+ pics inside of Demi and Joe…