Tuesday (Jan. 13) was just a regular weekday night in Nashville, Tenn., until Miranda Lambert made an exciting announcement on Twitter. The songstress surprised fans with a free show to preview her Certified Platinum Tour.

She took to Twitter in the afternoon to announce the concert, writing, "Been at rehearsals all week in Nashville for the #CertifiedPlatinum tour. We are so excited that we decided to kick it off right...so..."

Lambert's fans came out to support her, waiting outside Exit/In before the doors opened, and she did not disappoint. She thanked the packed house for waiting in the cold and admitted she and her band "were just ready to play for some people." Then, she promised, "We're going to do our set with some [other] stuff scattered in."

Lambert kicked off the show with 'Fastest Girl in Town,' 'Kerosene' and 'Platinum.' Other familiar tunes like 'Priscilla,' 'Over You,' 'House That Built Me' and her new single 'Little Red Wagon' were also on the extensive setlist.

She also gave her band members a chance in the spotlight. Gwen Sebastian, who was singing backup for Lambert, played an acoustic version of the Cranberries' 'Zombie,' and she did it so well that Lambert skipped out on what she had planned ('Famous in a Small Town') and had her bass player lead a cover of 'Bad to the Bone' instead.

The concert featured a packed set, and fans were treated to an encore consisting of lots of cover songs. RaeLynn and Sebastian kicked off the encore, joining Lambert for a gorgeous rendition of 'Cowboy Take Me Away,' made famous by the Dixie Chicks. The superstar also sang ZZ Top's 'Tush' and Wilson Pickett's 'In the Midnight Hour,' among others. Then, she and Sebastian closed out the show by covering Little Big Town's hit 'Girl Crush' (see video above).

"Has this been incredible, seriously?" Lambert asked the masses of fans in front of her. "I'm excited about the tour. If you catch us somewhere else, it won't be this crazy. But it will be [fun]."

Lambert's Certified Platinum Tour kicks off on Jan. 15 in Evansville, Ind. See a complete list of dates here.

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