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").

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

No band has a greater mystique than Led Zeppelin. Now, a stunning new documentary goes inside that legend and traces their origins.

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.

But as any superfan will tell you, "Becoming Led Zeppelin" ends when things are just about to get interesting: a pivot to acoustic folk, a plunge into drug abuse and