BLAKE SHELTON rocketed to superstardom as a coach on “The Voice,” but hard-core country rocker Eric Church ignited a feud when he blasted reality singing shows – and used Blake as an example!

“If Blake Shelton and Cee Lo Green turn around in a red chair, you get a deal? That’s crazy,” Church said in a 2012 interview, then added: “If I was concerned about my legacy, there’s no f*****g way I would sit there (and be a judge). Once your career becomes something other than the music, then that’s what it is. I’ll never make that mistake. I don’t care if I starve.”

Shelton, 37, was NOT happy about Church’s comments, saying: “I wish I misunderstood this.” Meanwhile, his wife Miranda Lambert noted that she got her start on the reality show “Nashville Star” and groused: “Thanks for saying I’m not a real artist.”

After the feud became major news, Church, also 37, backed off by saying: “I have a lot of respect for what artists like Carrie Underwood, Kelly Clarkson and my friend Miranda Lambert have gone on to accomplish,” but he stopped short of issuing an apology to Shelton.

“Those two don’t like each other to this day,” a source told The ENQUIRER. “Eric still thinks Blake sold out by appearing as a coach on a reality show just so he can sell more albums. And Blake, well, he thinks it’s just sour grapes from Eric because he’s more popular. I don’t think you’re ever going to see the two of them going out for beers together.”