Metallica returned to Nashville for their first concert in Music City in a decade on Thursday night (Jan. 24), and of course, it wouldn't be a  Metallica gig without a cover of the Loretta Lynn classic, "You're Lookin' at Country."

Wait a second ... WHAT?!

The thrash metal pioneers performed in the round at the Bridgestone Arena, and according to Nashville's Tennessean newspaper, their setlist featured a career-spanning cross-section of songs including "Seek & Destroy," "Harvester of Sorrow," "The Unforgiven," "Creeping Death," "For Whom the Bell Tolls," "Nothing Else Matters" and "Enter Sandman." Nine songs in, frontman James Hetfield and drummer Lars Ulrich took a break while bassist Robert Trujillo and guitarist Kirk Hamett offered up a two-man mini-set that kicked off with Lynn's classic hit, which reached No. 5 when she released it as a single in 1971.

Artists Who Unexpectedly Went Country

"We love Loretta Lynn, by the way," Trujillo tells the audience to introduce the song in the fan-shot video above. "We think she's here tonight. Kirk was supposed to sing this song, but he says he's too nervous. So I've gotta sing it, so help me out here ... if we blow it, don't kick our ass, all right? We're gonna have fun. It's a party, remember that."

Click the video above to watch Trujillo and Hammett's stripped-down performance of "You're Lookin' at Country."

The 86-year-old country icon appeared to confirm that she was in attendance when she shared a video of the performance via Facebook, writing, "Well, y'all ain't gonna believe this! Check out Metallica covering my song, 'You're Looking at Country.' Now I've seen everything. I loved it, boys! Keep rocking and it's good by me if you do a few more of mine. Maybe I'll have to sing one with you sometime!"

An all-star lineup will celebrate Lynn's life and music at a tribute concert on April 1 at Bridgestone Arena, just weeks before she turns 87 on April 14.

Garth Brooks, Trisha Yearwood, George Strait, Keith Urban, Miranda Lambert, Pistol AnniesAlan Jackson, Kacey Musgraves, Margo Price, Brandy Clark, Darius Rucker, Little Big Town, Martina McBride and Jack White have been announced to perform at the show, with more names to be announced. The big question is, will Metallica join Lynn onstage? We'll have to wait and see.

Loretta Lynn Through the Years: