seemed to be in quite an upbeat mood on Saturday night when she made her way to Club Robertson's Rasputin night in West Hollywood.
Right across the street from local celebrity favorite spot The Abbey, the "Part of Me" singer didn't go incognito as entered the venue with her purple hair capping off a red dress .
"The DJ announced a little after midnight that she was there," a club-goer tells PEOPLE. "She partied at a booth with a bunch of males who definitely appeared to be just friends. She had some kind of beverage in her hand."
Standing on a banquette at one point, the source says Perry "danced to Britney Spears
' s hit '...Baby One More Time.'
"Katy was in a roped-off area, but she was still accessible to her fans," the source adds. "She was posing for photos with people at the club and seemed to be having a great time." That's for sure: that night, the singer quoted Spice Girls on Twitter,
writing, "If you wanna be my lover you gotta get with my friends. #fact."
Once it was announced that Perry was on the premises, the source says, "The line got super long and it was really hard for people to get in." – Patrick Gomez