Rob Gronkowski -- All He Wants to Do is Dance (VIDEO)

Rob Gronkowski is a championship football player ... sometimes we forget, because it seems all he does is dance.

Gronk let loose at The Underground in Chi Town Friday night, sharing DJ honors with DJ Dante as he sang and danced with family and friends.

Gronk's in the Windy City for the Nascar Xfinity Series Race at the Chicagoland Speedway. He's the Grand Marshall.