With one of the most expressive voices in country music, Jennifer Nettles is always eager to stretch its boundaries. That proved to be the case on Wednesday night (June 4) in Nashville when she teamed up with R&B star John Legend on his romantic pop ballad, "All of Me."

Although the original version is a piano ballad, their elegant performance at the 2014 CMT Music Awards was based on a guitar arrangement composed by Hunter Hayes, who accompanied them onstage.

Legend and Nettles first met as performers at President Obama's inauguration in 2009, then became close friends as panelists on ABC's Duets in 2012.

The night before the CMT Music Awards, the Sugarland singer made her solo debut appearance at the Grand Ole Opry. In her dressing room, she explained to CMT.com why "All of Me" made her take notice.

"It's such a beautifully crafted, well-written song. It combines both beautiful imagery, and at the same time, has wonderful conversational moments, too," she said. "And then there are moments like 'Love your curves and all your edges/All your perfect imperfections.' Are you kidding me?! Obviously he just got married so the song was inspired by his love and by his relationship."

She continued, "The song is inspired and that is what I like about it. You can tell. It's not just storytelling. It is inspired from a sweet, sweet place within him. ... Musically and melodically, it's so beautiful. I love the fact that it's a piano ballad and it's at the top of the charts. It's been a long time since that's happened, and I would love to see it happen more and more."