Things can get pretty crazy late at night in Nashville -- as in, Kelsea Ballerini and a pop star singing karaoke at a dive bar-level crazy. The country star and fellow artist Halsey treated the patrons of Santa's Pub to an unexpected performance on Wednesday night (July 18).

Halsey, a pop singer known for hits such as "New Americana," "Castle" and "Him & I," performed at Nashville's Ascend Amphitheater on Wednesday night. Ballerini was in attendance with some friends and was, per Twitter, "100% ready to girl crush on @halsey tonight;" on Instagram, she admitted she'd be screaming along during Halsey's set.

Later that night, though, Ballerini found herself singing with Halsey, albeit at a much smaller venue. Video taken by Kalie Shorr (who also attended Halsey's Ascend concert) shows the two artists singing "Landslide" at Santa's Pub -- but that wasn't the only song they sang.

"Well me and @KelseaBallerini ended up doing a karaoke rendition of “Picture” by Kid Rock in a dive bar where no one knew our names," Halsey writes on Twitter, "so how was your night?"

Ballerini was home in Nashville during a brief break in her summer tour schedule. She's currently on the road with Keith Urban, opening shows on his Graffiti U World Tour.

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