It was a headline-grabbing collaboration: thrash legends Metallica paired with pop icon and closet metal fan Lady Gaga, but the pair's performance at the Grammys on Sunday evening was marred by technical difficulties, namely James Hetfield's mic being switched off.
As you can see from footage of Moth Into Flame above, Papa Het was forced to share a mic with Gaga, who lent harmonies and lead vocals to the Hardwired… To Self-Destruct track.
At the end of the performance, Hetfield threw his signature ESP across the stage in frustration.
We'd wager he's not as angry as Dave Mustaine, however, as when Megadeth went up to collect the award for Best Metal Performance for Dystopia, the house band burst into Metallica classic Master Of Puppets, naturally.
As you'll no doubt recall, Dave was fired from 'tallica prior to the recording of first album Kill 'Em All, paving the way for Kirk Hammett to join the band. It all makes the award ceremony's second Metallica-related cock-up rather awkward.
Read more about Metallica's journey to create Hardwired... To Self-Destruct in our in-depth interview with James and Kirk.