JASON ALDEAN is dating BRITTANY KERR, the "American Idol" reject he was caught making out with at a club back in 2012 . . . while he was still married. 

 

TMZ has a photo of Brittany backstage at his concert last Friday in Orange Beach, Alabama. She was also in the crowd at his show in Austin, Texas back in January.

 

After the pics went viral Jason had to come clean so his people confirmed to Taste of Country that the two started relations last April . . . right AFTER he and his wife filed for divorce.