Chris Brown partied with a bevy of hotties and with ex-girlfriend Karrueche Tran Friday night at Hollywood hotspot Emerson, celebrating his 23rd birthday with a party sponsored by ZING Vodka and Black Pyramid.

While on-again-off-again lover, Rihanna, is in New York for the Met Gala this Monday and for performances on her Diamonds tour, Chris partied it up in LA and X17 has the EXCLUSIVE pix from inside the club as Mr. Brown enjoyed the evening, surrounded by women.

While the cat's away ...