"Gwen was crying when we even just talked about singing it together at all," Shelton told ET at the time. "It just seemed to fit perfectly with our story, and, musically, I think it walks the line of what I can do and what she can do. Everything just kind of aligned and came together, and it's one of those once-in-a-lifetime moments."
The pair are also planning to perform the epic love song at the GRAMMY Awards on Sunday.
"Nobody but you, @gwenstefani, that I’d want to share this year’s @recordingacademy #GRAMMYs stage with! Tune-in Jan. 26th to watch our performance!" Shelton captioned an announcement of the news on Instagram.