A weekly dance party at B.B. King’s nightclub off Times Square turned bloody early yesterday when a man slashed three other men in a dispute over his girlfriend.

The still-unidentified thug went berserk over remarks the men made about his gal pal and slashed them in the face and neck with a razor at 2:30 a.m. during the hip-hop gig at the club on 42nd Street, cops said.