Gabrielle Union attended the opening of Hyde American Airlines Arena following the Miami Heat game in Miami on Tuesday.
The Think Like a Man actress – whose boyfriend Dwyane Wade plays for the Heat – sipped Dom Perignon and spent the evening with a group of friends.
"Gabrielle and her friends had an amazing time," an onlooker tells PEOPLE. The girls shared two bottles of champagne as deejay IRIE played hit after hit.
"Gabrielle and her friends even sang along to the music in unison!" the source adds.
– Kevin O'Donnell