Blake Shelton has a very special guest on his new album, Fully Loaded: God's Country. The country star's girlfriend, Gwen Stefani, duets with her love on the record's new single, "Nobody But You." Press play above to hear it.

"Nobody But You," the second track on Fully Loaded: God's Country, was written by Ross Copperman, Shane McAnally, Josh Osborne and Tommy Lee James. In a press release, Shelton says that he fell in love with the song the more he listened to it.

"I also realized how important it is for me and where I am in my life, and I think that’s why Shane was trying to get it to me," Shelton reflects. "It fits my story. I was about to go in and record when I decided that it needed Gwen on it – because it is our song. I think it’s magic."

"Nobody But You" is Shelton and Stefani's third recorded duet. Previously, the two teamed up for a holiday tune, "You Make It Feel Like Christmas," from Stefani's 2017 Christmas album of the same name, and for "Go Ahead and Break My Heart," which appears on Shelton's 2016 album, If I'm Honest.

“I was at The Voice compound, and Shane McAnally is on Songland, so they were there doing some cross-promotion. Shane came to my trailer and said, ‘Man, I got a song for you.' I knew he had Gwen’s number from a write, so I told him to send it to her as I was being called to set. I actually got the song twice because my producer Scott Hendricks emailed it to me right after," Shelton recalls of how "Nobody But You" made its way to him. "Then one day I was driving with Gwen, and I said, 'Hey let’s listen to that song from Shane, because Scott sent it to me too – it must be pretty incredible.' When I heard it, I was just floored. I realized how important that song was for me and where I am in my life right now.

"I just think it’s magical," Shelton adds of the song, which will be at country radio on Jan. 21. "I literally think it’s important of a song as I’ve ever recorded."

"Nobody But You" is one of five new songs on Shelton's Fully Loaded: God's Country album. Also a featured artist on the record -- which, in addition to the new tracks, includes some of Shelton's previous hits -- is Shelton's good buddy Trace Adkins, who appears on Shelton's newest single, "Hell Right."

Shelton and Stefani, a solo artist and the frontwoman of the rock band No Doubt, began their courtship on the set of The Voice, just as they were both emerging from highly publicized divorces. Shelton and Miranda Lambert announced their divorce in July of 2015, while Stefani and husband Gavin Rossdale, frontman for the rock band Bush, separated that August. Stefani and Rossdale had been married since September of 2002, while Shelton and Lambert had been married since May of 2011.

Shelton and Stefani officially confirmed their relationship that November, and have been together ever since. What started as a friendship forged in adversity grew into an unexpected love story, which Shelton says just keeps getting better.

"Every day that goes by, it just feels like a stronger bond between the two of us. It constantly feels like it's going to the next level," Shelton says. "That's the only way I think either one of us could probably describe it."

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