Little Big Town are having a massive success with their current single, 'Your Side of the Bed.' The plaintive ballad paints a stark portrait of a relationship filled with growing distance, and that theme is perfectly underscored by a duet vocal performance from singers Karen Fairchild and Jimi Westbrook -- who are married in real life. Interestingly, despite that impact, the song wasn't written or intended as a duet.

"When we wrote this song with Lori McKenna, we didn't know it was going to be a duet. We wrote it from one person's perspective," Fairchild tells CMT. "It was on accident that it became a duet."

She continues, "Clearly, Jimi and I live together, so when we were brainstorming on what should go on the record and what shouldn't, we were going through that song. There were just the two of us in the kitchen and we were like, 'Man, that makes a cool duet!'"

The resulting performance is so hard-hitting that when they were recording in the studio, one of their band members tearfully asked the couple if they were doing okay. The track's stark emotional honesty is a sharp contrast to the band's recent offerings.

"I have hopes for this song with the fans because 'Pontoon' has been fun and 'Tornado' has been this anthemic, I'm-gonna-rip-your-house-down song," Fairchild points out. "But this is about real life, living and the emotional connection we have with the fans when we sing it."