The fans lucky enough to score tickets to Miranda Lambert's intimate acoustic show at Nashville's City Winery on Wednesday night (Jan. 20) had already gotten lucky simply by being in attendance -- but they got even luckier when the country star debuted a brand-new song, "Scars."

The song was written by Scotty Wray, Lambert's longtime guitarist and good friend. Lambert told the audience that he's been playing the song for her for years, but "I was never damaged enough to sing a song called "Scars"" -- until now.

"We both had, like, a really, really s--tty year in 2015," Lambert said, an allusion to her divorce from Blake Shelton in July. "... But we're moving forward."

The singer called the song, which readers can hear by pressing play on the video above, "one of my favorite songs I've ever heard," and noted that she hopes to put it on an album sometime.

Ashley Monroe, Shane McAnally and Nicolle Galyon were also on the bill at the gig, which sold out in a mere seven minutes, but Charles Kelley, Maren Morris and Collin Raye also made appearances. Highlights included Galyon's rendition of Lambert's "Automatic," McAnally's performance of Kenny Chesney's "Somewhere With You" (which he wrote) and Lambert and the Raye/Wray brothers' version of the Eagles' "Desperado." Press play below to watch a snippet of the performance.

The show — an extension of Lambert’s all-female 2015 Roadside Bars and Pink Guitars Tour — benefited the Miranda Lambert Women Creators Scholarship at Belmont University, which provides scholarship funds to female students pursuing the goal of being in the music industry.

Before launching her Certified Platinum Tour in early 2015, Lambert played a similarly small club show, at Nashville’s Exit/In, which she announced mere hours before taking the stage. In late July, she performed another small acoustic show, at the city’s 3rd and Lindsley.

Watch Miranda Lambert, Collin Raye and Scotty Raye Sing "Desperado":

See Photos From the Roadside Bars and Pink Guitars: Unplugged Concert