Everything was good -- so very good -- when Miranda Lambert and Carrie Underwood put their voices together for "Somethin' Bad."

The reigning queens of country music came together to perform the rocker for the first time live on Sunday night (May 18) night at the 2014 Billboard Music Awards in Las Vegas.

The song is about what happens when good girls go (kind of) bad. Missing church, drinking too much, that kind of thing.

"I got a real good feeling something bad is 'bout to happen" is the lyrical hook. And from the looks on their husbands' faces, it's the kind of song the definitely lets the world know that Lambert and Underwood are not the kind of women you can push around.

Even though two powerhouse females singing together seems like a no-brainer, it doesn't happen often in country music. In 1993, Reba McEntire and Linda Davis (Hillary Scott's mother) had a hit duet with "Does He Love You," but this Lambert and Underwood song is the first major duet of its kind in more than two decades.

The song, written by Chris DeStefano, Brett James and pop music hit maker Priscilla Renea, will be featured on Lambert's upcoming album Platinum due out on June 3.

Other country performances from the show came from Florida Georgia Line, who performed "This Is How We Roll" with Luke Bryan (while Underwood and her husband Mike Fisher sang along from their seats) and Bryan, who sang his newest hit "Play It Again."

Country winners from the show -- described as the one where the Billboard charts come to life -- included Underwood, Bryan and Florida Georgia Line.

Underwood won the prestigious Milestone Award, and she made sure she thanked the fans first.

"I truly have the best fans in the world, and I wouldn't be doing one zillionth of what I get to do if it wasn't for them. They put me up here in the first place," she said before adding "my gorgeous husband, of course" to her list.

"I love country music. Thank you, God, for letting us be able to do it up here in front of all you guys tonight."

The top country artist award went to Luke Bryan, who was up against Blake Shelton, Darius Rucker, Taylor Swift and Florida Georgia Line. And "Cruise," the Florida Georgia Line song featuring Nelly, won the top country song award, beating out Blake Shelton with the Pistol Annies' "Boys 'Round Here," Darius Rucker's "Wagon Wheel," Luke Bryan's "That's My Kind Of Night" and Bryan's "Crash My Party."

Lambert, Underwood, Shania Twain, Brad Paisley and Lucy Hale served as presenters.