A few days after Metallica’s ill-fated Grammy performance with Lady Gaga, drummer Lars Ulrich has gone into detail on how pissed off James Hetfield really was.

Metallica jammed “Moth Into Flame” live with Lady Gaga at the 59th Annual Grammy Awards, but Hetfield’s mic remained silent until the song’s second verse. On Feb. 13, a stagehand was blamed for the technical difficulty, with a cable reportedly getting unplugged underneath the stage. After the song finished, Hetfield kicked over his mic stand and threw his guitar away hastily. He looked to be furious, and according to Lars Ulrich, Hetfield was.

“I haven’t seen him like that in 20 years,” Ulrich said on The Late Late Show With James Corden. “He was livid. He’s aged really well and he’s a pretty chill guy, but the first five or 10 minutes in that dressing room was not a lot of fun, but as they say, the show must go on and we fought through it.”

The Book of Mormon actor Andrew Rannells gave his own recollection of past technical difficulties during performances, while actress Katherine Heigl agreed that flubs can be the most enjoyable part of a show. Lars even went back into Metallica history, recalling an incredible Spinal Tap moment in England.

Watch Lars discuss Metallica’s Grammy mishap in the clip above!

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