They looked awfully chummy during their performance on the American Idol finale last May, but Adam Lambert and KISS rocker Gene Simmons are anything but these days, as the self-christened glam rock star and the “Hardest Man In Rock n’ Roll” bicker over a remark Gene made about Adam’s sexuality earlier this year.

Glambert is disgusted over Simmons insistence that coming out as gay — to the surprise of absolutely no one, mind you — would ruin his burgeoning career. During an interview with Good Day Philadelphia last June, Simmons advised the Idol runner-up to “shut up” about his preference for peen.

“Mostly he should shut up about his sexual preferences. We, America, the rest of the world, really don’t care,” Simmons said. “I mean, if the story becomes ‘I prefer farm animals to,’ you know, who cares?”

In an upcoming Rolling Stone article that has leaked online, Adam is quoted launching a scathing attack on Simmons: “Gene Simmons spouted something, that he thought I’d ruined my career by coming out. He’s obnoxious, and what a hypocrite – all he talks about is his sex life. He was being a dick – and he’s not the greatest singer.”