The 31-year-old "Bring Me Down" hitmaker joined Shania Twain over the gig from her Rock This Country tour, reported Us Magazine.
The pair posed together for an Instagram photo, after the show.
Twain, 49, later posted with the picture with caption, "Girls night, love seeing you! #RockThisCountry."
Lambert, 31, who thoroughly enjoyed the evening also shared a picture of her musical idol Twain, riding on a mechanical saddle around the arena.
"Shania Twain. Fringe Saddle. That's All. #nashville #girlsnight #rockthiscountry #musicismedicine," she wrote.