When Fuse interviewed the shock rocker last month, Cooper had this to say about the breakthrough act: "Mumford & Sons are great at what they do, but they're not rock. Don't call them rock. That's an offense to rock and roll."
So when Fuse News' Jack Osbourne caught up with the British band at Lollapalooza 2013, he asked for their response to Cooper's claim. "I don't think we have an ambition to be rock and roll; we're just playing music," lead singer Marcus Mumford says. "But I didn't know that rock and roll had rules. That's ironic to me. When you start setting rules for rock, you've passed it, haven't you?"
Watch Mumford's full response above and check out Cooper's original statement on the folk-rock outfit here.