Lars Ulrich From Metallica says his band weren’t ready for the backlash They would recieve after they released Lulu, their art-metal collaboration with Lou Reed.

Lars believes the heavy criticism was unfair on Velvet Underground icon Reed and describes him as a “sweet man” – before explaining how the pair nearly came to blows during recording sessions.

Ulrich tells Spin: “It was more spiteful than anyone was prepared for. Especially against Lou.

“When Metallica do impulsive riffing and Lou Reed is reciting abstract poetry about German bohemians from 150 years ago, it can be difficult to embrace.

“I understand that to some 13-year-old in Missouri, it can all seem a little cringeworthy. But to someone raised in an art community in Copenhagen in the late sixties, that was expected.”

Tensions boiled over during recording when Ulrich felt he had to tackle Reed over his attitude to an undisclosed topic. “I had to point something out about how things were functioning in the outside world,” says the drummer. “He got hot and bothered. He challenged me to a street fight, which is a pretty daunting proposition because he’s an expert in martial arts, and is never too far from a sword.

“The good thing about me is I can do the hundred-metre dash faster than most other 48-year-old musicians.”

Metallica will mark the 20th anniversary of their Black Album by playing it in full at this year’s Download festival at Donington, UK. But Ulrich admits there’s one track he’s not looking forward to as much as the others.

“Don’t Tread on Me has that shuffle vibe,” he says. “That’s not my thing. but I don’t wish to erase it from 97 bazillion copies of the Black Album.”

The band host their own festival named Orion on June 24 and 24 in New Jersey, and they’ve faced some criticism for the event lineup’s avant-garde nature. But Ulrich insists: “People gotta let us run amok. To be what everybody wants us to be would fucking kill us.”