Beyoncé at the 40/40 Club on Feb. 7
04/23/2012 at 04:00 PM EDT
Even new moms have to get their dance on! And Beyoncé
did just that Friday night. She joined younger sister Solange and two female friends for a girls' night out at New York City
's W.I.P. nightclub. The quartet let loose on the dance floor and jived to the club's mix of disco, '90s and hip-hop music.
"Beyoncé looked amazing and was having a great time with her friends," an onlooker tells PEOPLE. "She was very laid back, smiling and in a great mood."
Off the dance floor, Beyoncé, who gave birth to daughter Blue Ivy Carter
just three and a half months ago, chatted and shared some laughs with her pals while sipping on vodka drinks at a corner VIP booth. At one point, Oscar winner Cuba Gooding Jr. came to the table to say hello. The girls night out wrapped up around 3 a.m.
– Paul Chi