'The Voice' War! Inside Blake Shelton & Kelly Clarkson's Explosive Backstage Feud

The battle between the contestants on the current season of The Voice is nothing compared to the explosive war between longtime country coach Blake Shelton and newbie judge Kelly Clarkson! The two dueling divas went at it on-camera this week over who will nab this season's country star contestant and RadarOnline.com has exclusively learned their fighting didn't stop when camera's quit rolling. Find out what was said backstage that might cause Shelton to literally "Walk Away!"

Clarkson, 35 — whose mother-in-law happens to be country legend Reba McIntyre — came in swinging against existing coaches Shelton, 41, Adam Levine, 39, and Alicia Keys, 37, on her first season as a judge on The Voice!

RadarOnline.com was the first to report that there was some serious bad blood between Shelton and Clarkson prior to the season starting. In an interview at that time, Shelton said, “Make no mistake, Kelly is my friend, But when she's on this show, she is my enemy.”

That became clear on Monday night's episode, when the two went at it over country music contestants Wilkes, 33, and Jordan Kirkdorffer, 28. When it became clear to Shelton that Clarkson wanted to steal his top contenders, he said, "This is not a dating game. This is 'The Voice.'" But their bickering didn't end there, RadarOnline.com has learned.

As fans know, Clarkson inked an enormous contract to join The Voice this season and it seems to have been worth it, as the show's ratings have been through the roof — destroying competitor American Idol. "Blake went off on her over how much money she is getting paid and how unfair it is," the source said. "They fight over stupid things, like the size of a dressing room."