See Miranda Lambert, Oak Ridge Boys' Surprise Performance of 'Elvira'

Country Music Hall of Fame vocal group joins Lambert onstage during a New Jersey stop of her Livin' Like Hippies Tour

Miranda Lambert surprised her audience in Newark, New Jersey, on Thursday night with special guests the Oak Ridge Boys.

Miranda Lambert had just wrapped up a rare performance of "Airstream Song," a deep cut from 2009's Revolution, when her band began vamping a loose, slow-motion snippet of the Oak Ridge Boys' signature hit "Elvira" during Thursday night's performance in Newark, New Jersey. Lambert sang along, leading the Prudential Center through the familiar words. Then the music stopped.

"You know what would be even cooler?" she asked, her hands on her hips. "If the Oak Ridge Boys were here to sing this song with us."

With that, longtime Oaks bandmates Duane Allen, Joe Bonsall, Richard Sterban and William Lee Golden walked onstage as the band launched back into the song. Together, the group performed a co-ed version of "Elvira" featuring Lambert as the group's fifth member, with gang vocals from an entire arena's worth of fans.

The Oak Ridge Boys weren't the only additions to Lambert's show. Launched in January, her Livin' Like Hippies Tour welcomed opening act Charlie Worsham to the bill with Thursday's gig. Worsham's time with the tour will be brief, coming to a close at the end of Saturday night's show in Winston-Salem, North Carolina. Even so, the Livin' Like Hippies trek rolls on for another handful of dates, eventually wrapping with a festival appearance at the County Jam Ranch in June.

The Oaks recently released their new album 17th Avenue Revival, a gospel-leaning project produced by Dave Cobb, while Lambert will release her song "Keeper of the Flame," off the double LP The Weight of These Wings, to country radio.