It looks like Brit-Brit’s undergoing a serious case of shaver’s remorse, but that doesn’t stop her from getting her party-on.

A blond wigged Britney hit up the Roxy nightclub in Hollywood for a karaoke-themed birthday party.

She left after 45 minutes and went to the Polo Lounge instead, but got upset after the DJ played her hit ‘Hit Me Baby One More Time.”

One clubber at the lounge said: “It was a shock to see her in a wig after what she had done to herself. While she was in the club she kept going to bathroom all the time, which was weird.”