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James Hetfield

Metallica's James Hetfield has conceded that the band could "fall apart" at any moment.

The frontman formed the heavy metal band in 1981 with drummer Lars Ulrich, with the current line-up also comprising of guitarist Kirk Hammett and bassist Robert Trujillo.

Metallica are currently touring their tenth studio album Hardwired... to Self-Destruct, but in spite of their continuing success Hetfield has admitted that they are always on the verge of breaking up.

"The band can still pretty much fall apart at any moment," he told Rolling Stone. "But we don't want that. We know too much now... I know that's a strange word in this business, but we care too much. We know where all the nuclear buttons are with each other, but we don't push 'em. We love what we do, and we want to keep it going."

Hetfield also hinted at some ongoing tensions between himself and Ulrich. The 53-year-old explained that Ulrich tends to worry about production details and curfews set at stadiums.

"Sometimes Lars' plate is too full and he won't admit it," he sighed. "He'll show up in the Tuning Room late, all wound up. So I remind him, 'You can say no. You don't have to do everything.'"

Meanwhile, the California native explained that they don't really have to practise their songs prior to gigs as they have performed them so many times. Nowadays, the group takes a more "athletic approach" to concerts and are focused on finding methods to keep the set fresh.

"It's more about warming up " it's like an athletic approach where you gotta get the blood flowing. Sometimes it's hard not to get a little adventurous or curious in the certain part because you just have to try and find ways to keep your attention focused," he added.