Keith Urban loves to collaborate with other artists. “The Fighter,” his duet with Carrie Underwood, is the No. 1 song on the Mediabase chart this week.

In 2013, Keith teamed with Miranda Lambert to sing “We Were Us,” saying, “[Miranda] was the first artist that popped into my head. She opened some shows for us a few years ago and we would do a song together each night, and I always loved how our voices blended together.”

Last week (July 26) at the California Mid-State Fair in Paso Robles, Calif., Keith invited special guest Lauren Alaina onstage during his set to treat fans to a performance of “We Were Us.”

“We don’t get to do this song . . . uh . . . ever in our set,” Keith said, “but I heard Lauren sing it, and I’m like, ‘You gotta come up and sing this song with me.’”

And Lauren did.

Watch the video of their performance below.