Metallica drummer Lars Ulrich has said the band's former rivalry with Megadeth, Anthrax and Slayer was childish.
The four bands, who have recently been touring together under the title Big Four, endured often bitter feuds during the 1980s and 90s.
In an interview with Rolling Stone, Ulrich said: “When you get out of the sandbox and grow up, you stop worrying so much about what everyone else is doing.
“To me, the competition is now internal. That's the biggest difference from twenty years ago.”
Slayer's guitarist Kerry King added that the four bands had always been “friendly rivals”.
The Big Four shared the same stage at the Sonisphere festival earlier this summer – check out photos below.