Joe Jonas Celebrates DNCE Anniversary ... Before Big VMA Night

Joe Jonas hasn't yet won the 2016 MTV VMA 'Best New Artist' award ... but he and his band partied like they did.

Jonas, JinJoo Lee, and Cole Whittle performed at Up & Down for DNCE's 1st anniversary.

Big Sean also stopped by to show his support before Joe and Co. go up against Desiigner, Lukas Graham, Bryson Tiller, and Zara Larsson for the prestigious "Moon Man."