B. Scott and Mariah Carey
05/11/2012 at 06:00 AM EDT
Already celebrating because of President Obama's announcement in support of same-sex marriage, the crowd at The Abbey Food and Bar in West Hollywood was in for an even bigger treat when Mariah Carey
showed up out of the blue Wednesday night.
"There was no formal announcement that she arrived at the club, but she and her friend B. Scott held court at one of the main dance floor tables – so she was very visible," a partygoer tells PEOPLE of the singer, who recently renewed her vows
in Paris. "She was very nice and gracious."
In honor of Carey's appearance, the deejay started playing her songs, which caused the ladies on the dance floor to "go crazy," the source says.
Even though the pop diva, who stuck around until 2 a.m. and took some shots of Beluga vodka, kindly posed for pictures with many people at the club, the insider explains, "A security guard had to stay by her booth to control her fans." – Dahvi Shira