The title track of Ashley Monroe's new The Blade album is a duet with Miranda Lambert, so when she didn't appear during Monroe's performance of the song at the Basement in Nashville on Wednesday night (July 22), it seemed unlikely the two friends would share the stage at all that night. Fans got a surprise when, during the encore, Lambert stepped out for her first public appearance since the news of her divorce.

Wearing a black dress she admits she bought at Target, Lambert helped Monroe close the show with an unrehearsed version of "Heart Like Mine," a song the two wrote together for Lambert's Revolution album. Monroe asked the crowd to show her best friend a lot of love, and they didn't hold back. Both singers appreciated the heavy applause. Lambert sounded and looked fit for the evening — if she's been spending the last few days sobbing, it didn't show.

In fairness, Monroe's album release party — The Blade hits stores and digital retailers on Friday (July 24) — would have been special without Lambert. Vince Gill and the Striking Matches were two of the "and Friends" who took the stage with the "On to Something Good" singer. Gill sang harmony on "Weight of the Load," a song he co-wrote with Monroe. He also produced the album.

Sarah Zimmerman and Justin Davis of the Striking Matches were the first guests of the evening, joining the blonde crooner for “From Time to Time” (inspired by Monroe’s late father) and “Dixie.” Songwriters Steve McEwan and Jessi Alexander also took the stage with her later in the show, as stars like Meghan Linsey, Little Big Town’s Phillip Sweet and Nashville’s Sam Palladio (Gunnar) watched from the audience.

The concert was recorded and played on SiriusXM Wednesday night, so many of the fans were listeners of the Highway. The invite-only audience witnessed the singer play her entire new album, as well as songs from Like a Rose. Her only cover was Lambert’s “Heart Like Mine,” and really it’s tough to call that a cover.

Earlier in the night, Lambert’s absence on “The Blade” was telling, and likely intentional. The heartbreaking ballad is about the end of a relationship and includes the lyric: "You caught it by the handle / And I caught it by the blade."

As she performed it alone, the always-emotional Monroe seemed especially moved, almost to the brink of tears. “The Blade” was written by Marc Beeson, Jamie Floyd and Allen Shamblin.

Ashley Monroe Talks About Her Emotional Duet With Miranda Lambert