Halsey is in her 'dirtbag girl' era ... the songbird was seen in a black lingerie bra and matching underwear as her dark hair was in tangles around her face. The stunner was also seen flashing ...

She teamed the high-cut pleated frock with a set of matching black leather stiletto boots and a handbag in the same color. Wearing her dark hair in a ... mahogany shoes. Halsey's latest sighting ...

For Halsey, musical stardom and beauty entrepreneurship aren't all that different. The About-Face founder said that the brand's name, for instance, struck them much the way songwriting does.