Shelton, 44, shared a teaser for the song, titled "Happy Anywhere," Monday on Instagram.
"Real excited to share this one with y'all and honored I was able to talk @gwenstefani into doing another song with me! #HappyAnywhere out THIS FRIDAY!" he captioned the post.
Stefani, 50, promoted the song in a post on her own account.
"yes please @blakeshelton so excited and grateful about that this song! thank u - can't believe my luck gx," she wrote.
Shelton and Stefani will perform "Happy Anywhere" for the first time Friday during the Today summer music series. The song is inspired by the couple's experience in "quarantine" amid the coronavirus (COVID-19) pandemic.
"Even though Gwen and I just had a single out we decided that, under the circumstances, this year... man, there's never been a better time for 'Happy Anywhere,'" Shelton said in a statement.
"We've all been in quarantine and lockdown, and hopefully we've been doing that with somebody that we really love and enjoy being around," he added. "That's what happened with Gwen and me this summer -- and this entire year."
Shelton and Stefani released the single "Nobody but You" in January. The couple previously released the songs "You Make It Feel Like Christmas" and "Go Ahead and Break My Heart."
Shelton and Stefani confirmed their relationship in 2015 following their respective splits from Miranda Lambert and Gavin Rossdale. Stefani referred to Shelton as her "best friend" while celebrating his birthday in June.