Rita Ora brought some special friends to the Charli Xcx show in London tonight. The "Black Widow" singer revealed that she opted to go braless for her pal's concert when she was spotted wearing a sheer black turtleneck that ultimately flashed her nipples to paparazzi as they snapped pics of the star leaving O2 Shepherd Bush's Empire. She did attempt to slightly cover up, though, by wearing a large, furry black coat over her outfit, which also included a pair of black leather pants and boots. Granted, Ora may have gotten really into the show and therefore taken off her bra to throw it on stage, but considering her outfit, that would have been extremely difficult and annoying. Right?!...