Gabrielle Union was dancing her ass off at the Pride Festival in Miami Beach this weekend ... and it was all to show support for her 11-year-old stepson, Zion.
Zion is Dwyane Wade's son from a previous relationship but he lives with Dwyane and Gabby full time and Gabby treats him like blood.
While Wade wasn't at the event -- the Miami Heat had a game in Toronto -- the NBA star was certainly proud of his family, saying:
"Zion had his own cheering section today.