The Grand Ole Opry celebrated its 90th birthday over the weekend (Oct. 2 and 3), and in addition to the pre-announced, expected performances, by everyone from Carrie Underwood to Old Crow Medicine Show, the Opry's 90th Birthday Bash featured a few surprises -- such as a collaboration between the Oak Ridge Boys and Little Big Town on the Oaks' classic hit "Elvira."

During Friday night's (Oct. 2) show, the two quartets joined forces on the tune from 1981. Press play on the video above to see a snippet of their performance.

After they concluded the song, both the Oak Ridge Boys and Little Big Town were presented with Grand Ole Opry 90th anniversary member gifts: replicas of new backstage artwork.

"For 90 years, Opry members have been the heart and soul of the show that made country music famous," said Opry Vice President and General Manager Pete Fisher. "Moments like these connecting generations of great country artists are what the Grand Ole Opry is all about."

In addition to the star-studded evening shows, the two-day celebration in honor of the Opry's 90th year featured backstage tours, free concerts on Opry Plaza, food trucks, a beer garden, a chili cook-off, games, prizes and more.

The Grand Ole Opry began in 1925 as a simple radio broadcast, and through the years, the country institution has showcased both legends and new hit artists, earning the title of “country’s most famous stage.”

See Little Big Town + More Country Stars Then and Now

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