Charlie Worsham's show on Friday (June 10) at the 2016 CMA Music Festival was already a surprise ... but those in attendance got an even bigger surprise when Eric Church showed up. The two collaborated on a cover of the Band's "Ophelia."

"Sometimes CMA Fest brings the unexpected," a Facebook post on Church's page reads, "and a 1AM jam with Charlie Worsham in a 130F-degree room is right up there."

The "secret" show took place at Ernest Tubb Record Shop on Lower Broadway, and also featured an appearance by Brandy Clark. The Tennessean reports that although "dozens" of fans were able to make it into the small, non-traditional venue, Nashville Metro Police had to be called to help control the crowd outside.

Earlier on Friday night, Church performed during the festival's Nissan Stadium show. The evening's lineup also included Sam Hunt,Chris Stapleton, Carrie UnderwoodHank Williams Jr.Frankie Ballard and Clint Black. Readers can press play on the video above to watch his performance with Worsham.

Church and Worsham's performance was not the first time that Church has covered the Band: He has been known to break out "The Weight" in concert. In fact, he performed the song during the 2015 CMA Music Festival, at Marty Stuart's Late Night Jam.

See Photos From CMA Fest 2016, Day 2