You just never know who might end up onstage at a Taylor Swift concert. The country-turned-pop superstar surprised fans at a show in Los Angeles on Monday (Aug. 24) by bringing Dixie Chicks lead singer Natalie Maines out to duet with her on one of the trio's biggest hits, "Goodbye Earl."

"If not for this woman and her band, I would not have known that you can be quirky, and fun, and yourself, and outspoken, and brave and real," Swift begins her introduction. "When I was 9 years old and got her first CD, I wouldn't have dreamed the things that I dreamed, and I wouldn't be standing on this stage today."

She goes on to say that "the song we're about to sing was my go-to talent show song. I've sung it probably 7,000 times in my life, and I just have a question: do we have any Dixie Chicks fans in the house tonight?"

The audience goes crazy as Maines emerges from the wings in the clip above, which was filmed by a fan at the Staples Center in L.A. during a stop on Swift's current 1989 tour. The women trade verses and join together on some of the choruses for the offbeat song, which was a huge hit for the Chicks in 2000 despite the fact that the lyrics describe how two childhood friends named Wanda and Mary Ann murder Wanda's husband, Earl, by poisoning his black-eyed peas after he repeatedly abuses her.

In a humorous take on the subject, they get away with it because "the weeks went by and spring turned to summer / And summer faded into fall / And it turns out he was a missing person who nobody missed at all."

Maines and Swift deliver an energetic, playful and thoroughly engaging performance, romping around the stage, trading lines and getting the audience to sing along in what must have been a dream come true for Swift. The song ends with them out at the end of the long ramp into the audience, bathed in lights as the crowd erupts in cheers for the one-of-a-kind performance.

Swift shared her excitement via Facebook after the show, calling the experience "unbelievable."

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