(Cover) - EN Showbiz - Will Smith treated Gabrielle Union to an impromptu concert at her 40th birthday bash.

The Bring it On actress celebrated turning the landmark year with a star-studded party in Miami, Florida on Saturday night.

A video posted to YouTube on Sunday shows Will taking the stage alongside Doug E. Fresh.

The Welcome to Miami hitmaker is seen grabbing the microphone for a freestyle rap while Gabrielle laughs in the background.

The rappers then perform a remix of Will's 1991 hit Summertime and the theme song from his 1990s American television sitcom Fresh Prince of Bel Air.

The five-minute clip shows Gabrielle walking to the stage to give the pair a hug.

Doug E. Fresh goes on to perform another track with fellow rapper Lil' Vicious.

Gabrielle will turn 40 on Monday.

The actress took to Twitter to gush about her wild night out.

"I'm sittin here thinkin about last night & I'm just cheesin & shakin my head. Unreal & epic! Big S/O (shout out) 2 everyone who was a witness," she wrote. (C) Cover Media