Taylor Swift and Nelly don't seem like a likely combination, but that hasn't stopped the country music crossover star from rubbing elbows with the St. Louis native on several occasions. During a Red Tour stopover in Nelly's hometown this week, Swift shocked her audience when she brought the rap star on stage.

In between songs, Swift paused to tell the audience how much she loves their city, mentioning the St. Louis Arch and a few other attractions. But then, she kept going.

"[When I think of St. Louis] I mostly think of the fact that one of my favorite artists is from here," Swift continued. "What would you say if I told you that Nelly is here?"

Naturally, the crowd erupted in screams and applause when Nelly descended from a large staircase in the middle of Swift's stage set up. Looking cool in casual red pants, a striped top and sneakers, Swift met him at the bottom of the steps to begin their duet.

The rap star sang his latest hit, 'Hey Porsche,' with the help of the 'Red' hitmaker. Swift and Nelly strutted all over the stage together, walking onto platforms to get closer to the audience. Throughout the song, the country songstress showed that she could have a career in rap music, too, as she acted as Nelly's hype man -- er, woman -- and encouraged the audience to jump and wave their hands.

Although Swift and Nelly aren't the first duo that come to mind when you consider collaborations, this isn't the first time that the two megastars have teamed up. On a St. Louis tour stop in August 2011, Swift covered Nelly's 'Just a Dream.'

Then, just a few months later when Swift was in Houston, Nelly joined her onstage and they sang 'Just a Dream' together.

Could this continual collaboration point to a joint single in the future? Swift's labelmates Florida Georgia Line recently teamed up with the rapper for a 'Cruise' remix, so it's only fair that she get in on the action, too.