Jack White DETESTS The Black Keys -- in particular BK singer Dan Auerbach -- and the confession was made in the middle of Jack's very nasty divorce.

Jack's wife Karen Elson submitted a bunch of emails to a judge, claiming he was a threat to her safety. Frankly, we've read the emails and they're not that threatening, but what really stands out is Jack's venom over Dan and the band.

Jack is clearly pissed his kids are being enrolled in the same school as Dan's kid, writing, "My concern with Auerbach is because I don't want the kids involved in any of that crap ... That's a possible twelve f***ing years I'm going to have to be sitting in kids chairs next to that a**hole with other people trying to lump us in together."

He adds, "[Auerbach] gets yet another free reign to follow me around and copy me and push himself into my world."

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