DECIDER spoke to director-writer Bernard MacMahon and producer-writer Allison McGourty about this project that was decades in the making.

In retrospect, it makes sense that backing Bassey would prove formative: So much of Led Zeppelin was about power, poise and drama (or melodrama, if you think of the first album's overwrought "Babe I'm Going to Leave You").

Becoming Led Zeppelin is already nearing $6 million in international box office gross. In an era where most documentaries head straight to streaming, the rock doc's box office run – not the mention the fact that it's playing on IMAX screens – is a small coup.

Full of never-before-seen footage of the band’s first 18 months, interviews with John Paul Jones, Jimmy Page, Robert Plant, and new audio from the late John Bonham, the first authorised documentary about the best hard rock band to ever do it assumes a lot about what its audience already knows.