Classical music does not get any cooler than mezzo Vesselina Kasarova. She jived. She grooved. She shuffled. She shimmied. She possessed the Barbican stage last night, an awesome black jumpsuit hanging off her rangy, kinetic figure, her neck sliding about like an Indian dancer's, her feet (in kitten heels) spinning like a jazzer's, her bullying arms posturing and prodding, her mouth flashing its whites like a primate's. Her voice? Extraordinarily weird, moving, honest, explosive. Her Sta nell'Ircana was a theatrical moment of the year.