Madonna: Truth or Dare at 30 – the most revealing pop star documentary ever?

A promotional image for Madonna: Truth Or Dare. Photograph: Miramax/Allstar   When teenage pop phenomenon Billie Eilish recently unveiled a drastic new image on the cover of Vogue magazine, the internet went into feverish overdrive. Previously distinguished by raven-dark locks and loosely androgynous, body-concealing attire, the singer instead turned to hyper-feminised exaggeration: bombshell-style platinum curls atop a tightly…