It was a once-in-a-lifetime moment for fans of Luke Bryan and the Doobie Brothers when the country superstar teamed up onstage with the classic rock stalwarts.

Bryan joined the Doobie Brothers onstage in Nashville in 2011 for an episode of CMT's Crossroads, which pairs country artists with acts from other genres. Taped in May of 2011, the special performances aired on June 24, 2011.

The "Fast" singer lent his voice to Doobies classic including "China Grove," "Old Black Water" and "Long Train Runnin'" during the broadcast, and they returned the favor by joining him for songs including "Do I," "Rain Is a Good Thing" and "Country Girl (Shake It for Me)."

Artists Who Unexpectedly Went Country

The collaboration wasn't that big of a stretch for Bryan, since their music had been a longtime influence.

"Their music was such an iconic part of my growing up. I bet most Americans can hear a particular Doobie Brothers song and have it take them back to a certain time and place in their life … and the best thing is, they are still creating great music today!" he said at the time.

Check out their performance of "China Grove" in the video above.

The Doobie Brothers went on to collaborate with a number of country artists on 2014's Southbound, which featured them covering their own past catalog with help from some of country music's biggest stars. Singer-guitarist Tom Johnston told Taste of Country that making the classic songs work in country arrangements was not that challenging.

"In fact, we had some songs that are pretty much already there in a sense, like ‘Black Water’ and things like that," he noted. "Not full-out country, but it’s not a stretch of the imagination to get them there."

See Luke Bryan's Most Unforgettable Moments

More From 98.1 The Hawk