Saturday night (March 17) Miranda Lambert and her touring crew hit Broomfield, Colo.'s 1st Bank Event Center. During her show, Lambert invited another powerful female vocalist -- and fellow 'The Voice' mentor -- to take the stage with her. Surprising the audience, Kelly Clarkson emerged and offered up her recent single 'Stronger (What Doesn't Kill You)' from her fifth studio album, 2011's 'Stronger,' as well as Lambert's own 'Gunpowder and Lead' with the help of the blonde country starlet herself.

Following their first number, Lambert screamed, “Holy s--t! Kelly Clarkson is here, Colorado. She’s here tomorrow night, so you better get you’re a-- here to see her!"

“This is the first night to see Miranda," Clarkson gushed into the mic. "She’s kicking a--. I’ve been a fan since ‘Kerosene,’ so I’m a true fan.”

“She’s Kelly Clarkson. Whatever," Lambert countered, ducking the compliment. "She wanted me to sing that y’all, and I was like, ‘Dude, if I could sing like you I wouldn’t ever talk. I would sing everything.’ But she does love this song ... This is all about girl power—that’s what we’re both about.”

With that, Clarkson joined Lambert on her sassy revenge anthem 'Gunpowder and Lead' from her 2007 record 'Crazy Ex-Girlfriend.' The first-ever 'American Idol' winner offered her killer vocal chops to the song, taking the higher parts while Lambert's voice played in the lower register and drove home the song. Together, the two were a female vocal duo on fire with energy and strong, sing-it-like-you-mean-it vocals. Surely, this was a special treat for the roaring Colorado crowd.

Watch Miranda Lambert and Kelly Clarkson Perform 'Stronger (What Doesn't Kill You)'

Watch Miranda Lambert and Kelly Clarkson Perform 'Gunpowder and Lead'