Metallica is the sort of band who overdocuments. For all its fascinating internal dynamics, their Metallica: Some Kind Of Monster documentary was, after all, 141 motherfucking minutes long. A week and a half ago, the band performed a fascinating incendiary clusterfuck version of their song “One” with the classical pianist Lang Lang; I was pretty drunk by that point in the broadcast, but I really liked it. And now the band has posted a 21-minute video of rehearsal footage for that performance, wherein we get to see how obsessively the band pieced the collaboration together.

Best part (that I watched): The fist-bumps at 12:24.