Blake Shelton gave the crowd at his show on Thursday night (Feb. 20) the ultimate treat, inviting girlfriend Gwen Stefani out as a surprise guest.

Shelton was in the middle of his set at the Mechanics Bank Arena in Bakersfield, Calif., when he introduced his girlfriend of four years, bringing her out to sing their duet "Nobody But You."

In a fan-captured video shared via Twitter, the two face one another as they sing, "Got no regrets 'cause it got me here / But I don't wanna waste another one / I've been thinking about what I want in my life / It begins and ends the same / If I had to choose what I couldn't lose / There'd only be one thing."

Stefani drew massive cheers of support from the crowd as she pointed to Shelton during the latter two lines.

"Nobody But You" is featured on the country superstar's latest album, Fully Loaded: God's Country. It was Stefani who heard the song first, as she was working with songwriter Shane McAnally who said he had a song he wanted to pitch to Shelton.

"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," Shelton explains to Entertainment Tonight. "Everything just kind of aligned and came together and it's one of those once-in-a-lifetime moments."

The couple also performed the song together the night before, on Wednesday, during Stefani's Las Vegas show. She has a residency there, but when they're not onstage, the couple tends to spend time at Shelton's Oklahoma ranch.

"Nobody But You" is currently in the Top 10 on the Billboard Hot Country Songs chart.

Blake Shelton Covered Alan Jackson and the Crowd Was All About It!

See Country Music's Best Love Stories:

More From 92.9 The Bull