When Miranda Lambert and her boyfriend Anderson East criticized one of Blake Shelton‘s idols recently, he made a surprising decision to get involved. Now, two years after The Voice coach blindsided the blonde beauty by filing for divorce after four years of marriage, a new war between the exes has erupted — and it includes revenge songs, public digs, and trash talking to pals.

“There is still a lot of bad blood and unresolved anger between Blake and Miranda,” a source tells Life & Style exclusively. “No one thinks they will ever be able to bury the hatchet and put their issues behind them.” Adds a different insider, “A whole new era of warfare is starting for Miranda and Blake.”

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The unlikely spark? Country legend Garth Brooks choosing to lip-sync at the Country Music Association Awards. The move irked Anderson, 30, who was at the star-studded event alongside Miranda. On Nov. 9, he wrote that the Entertainer of the Year’s decision to not sing live “truly offends me. I was told country music is three chords and the truth.” Miranda, 34, quickly backed up his sentiments. “High five on this babe,” she commented. “If you can’t sing then don’t. It’s better to be honest than to pretend. I think it’s bulls–t.”

Blake had read enough. “It was just absolutely uncalled for that Miranda and Anderson made public comments about Garth’s performance,” says the source. “Miranda crossed the line, especially because Garth had been a very close friend to the couple when they were married. Blake was livid.” So, in a clear dig at his ex, the “I’ll Name the Dogs” singer (who did not attend the CMAs) took sides, tweeting out his support for the industry veteran on Nov. 10: “@garthbrooks…I still love you. #hero #respect.”

The 41-year-old has made other slights in private, says the source. “Blake isn’t a guy who goes around trash-talking people, but when his ex comes up around friends, it’s never in a flattering way. Blake has always felt that Miranda betrayed him and cheated on him. He has never gotten over it and probably never will,” the source adds.

It didn’t help that Miranda dished about their split on her 2016 album The Weight of These Wings. “If you want to hear my side of the story or my opinion of what happened, it’s all on there,” she admitted. “There’s no mystery anymore.”

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Upcoming songs will likely touch on how “Blake didn’t work at the marriage like she wanted him to,” says a third source, alleging that his big move to LA for The Voice was a factor in the split. “She’ll pen lyrics about how he became distant. Blake and Miranda used to poke fun at Hollywood and its many posers.”

For Miranda, revenge songs are where the war with Blake ends. “[She] is the undisputed queen of contemporary country music,” the insider says of the 2017 CMA Female Vocalist of the Year winner. “She’s found love the second time around and is thriving. She truly feels that living well is the best revenge.”