Kings Of Leon stars CALEB and NATHAN FOLLOWILL have drawn a blank on the studio fight that left the singer with a broken arm and his brother with injuries - they can't remember why they were scrapping.
The famous fisticuffs became so violent that an assistant cleared the room, so the siblings could get physical.
Frontman Caleb tells Rolling Stone magazine, "We still don't know (why it started). It was a big one, though.
"We were really drunk, and one of us said something really deep and hurtful and that was it.
"Our assistant shuffled people out the door when he knew it was about to go down, and once the house cleared, it was like they let two dogs off their chains - we went crazy. It was just a good old Wednesday night in Nashville (Tennessee)."