Caught in the Act

Katy Perry Celebrates Her Brother's Birthday – Without John Mayer

08/14/2012 at 06:00 AM EDT

No guy, no problem! Katy Perry left rumored beau John Mayer at home Friday night while hitting West Hollywood's Bootsy Bellows. The singer, on hand to celebrate her brother David's birthday, kicked back as his band performed.

Hanging with her friend Markus Molinari and her stylist, Johnny Wujek, Perry "seemed very happy and she was really having fun," an onlooker tells PEOPLE.

Also unwinding at Bootsy Bellows Friday: Leonardo DiCaprio and pal Lukas Haas; venue owner David Arquette; and Glee's Naya Rivera, Chord Overstreet and Kevin McHale.
– Jennifer Garcia

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— People magazine (@peoplemag) August 7, 2012

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