Taylor Swift’s artistic persona has undergone one heck of a shift recently.

Swift, who entered the public consciousness as a dorky girl jealously watching the cheer captain from the bleachers, has been doing some growing up. On “Reputation,” her latest record, Swift has learned some potent new words, is drinking whiskey on ice and wine in the bathtub, and buying dresses whose sole purpose is being pulled off by a man.

This ain’t the same girl who was singing about Romeo and Juliet.

But even those changes didn’t prepare us for Swift’s new role: the other woman.

Wait … what?!

First, the setup.

Sugarland, the country outfit from Georgia, released the music video for its song “Babe” on Saturday. While the band performs the song (with Swift on background vocals), the pop star and Train’s Pat Monahan actually wrote the tune, which was originally slated to appear on Swift’s fourth record, “Red.”

Swift’s authorship is clear once you dig into the lyrics a little bit — it tells the tale of a spurned lover lamenting that her partner cheated, a common Swift theme.

Here’s a prime excerpt:

What a waste
Taking down the pictures and the plans we made, yeah
And it’s strange how your face doesn’t look so innocent
Your secret has its consequence and that’s on you, babe
I break down every time you call
We’re a wreck, you’re the wrecking ball
We said no one else, how could you do this, babe?

Because Swift didn’t end up using the song, she decided to give it to Sugarland, which got its start around the same time she did.

“Swift reached out. We [have] obviously known each other for many years. When she was first getting started we had just had our first little EP out, called ‘Premium Quality Tunes,’” Sugarland’s Jennifer Nettles told Billboard. “She still has a copy of it that we signed for her whenever we played a couple of shows together. She was excited we were getting back together and reached out and said, ‘Hey, I have a song.’ That is a shortlist, ladies and gentleman, of people to whom she has said, ‘Hey, I have a song, you want to sing it?’ So we said, ‘Yeah!’ ”

“We’ve never really put a song by anyone else on our records, so we weren’t really used [to] sorting through that and we didn’t want to mess it up, so we didn’t tell anybody until we got it finished and she liked it. Thank God. Because it is a good song,” fellow Sugarland member Kristian Bush added.

Given her connection to the song, Swift appeared in the video.

But in a clever bit of role-reversal, the devastated wife singing the song is portrayed by Sugarland singer Jennifer Nettles, while Swift plays the human wrecking ball that destroys the marriage.

“It’s your favorite summer movie you haven’t seen yet,” Bush told ET. “It’s redheaded Taylor. Which I think is … it could be a giveaway if you’re a ‘Mad Men’ fan, but maybe not.”

Without spoiling the show for anyone who hasn’t seen it, rest assured the video borrows heavily from the 1960s-set drama. It was even shot on the Los Angeles set where AMC filmed “Mad Men.”

Actor Brandon Routh plays the philandering husband, as he heads to his office — where a redheaded, seductively dressed Swift waits like a lioness stalking her prey. Swift, as a femme fatale, puts on her best vixen look and seduces Routh, only for Nettles to show up and walk in on them engaging in some pretty inappropriate office behavior.

It’s an interesting turn for Swift, who so often plays the victim. And she nails the role, but maybe that’s not so surprising, given that the video was her idea in the first place.

“She actually reached out to us and said, ‘I’ve got a great idea for the video,’ and she wrote the treatment,” Nettles told People.

“And we looked at it and said, ‘Oh my gosh, this is awesome,’ ” Bush added.

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