Practically everyone's heard Katy Perry's "curious" tale about kissing a girl by now, but never quite like this. Talented singer-songwriter William Fitzsimmons has turned the pop track "I Kissed a Girl" on its head in a subtle new acoustic version, with a comment on cheating to boot.

Listen to our exclusive stream of the cover below.

"I first heard this song when I was processing a lot of mistakes I had made in the last few years, and I actually conceptualized it from the perspective of infidelity, looking elsewhere for what one should only get from their respective other," Fitzsimmons tells HitFix.com of "Girl." "It certainly wasn't the original intent of the song, but for where I was at the time that's what I heard.  When you conceive the song from that perspective, it takes on a very formidable and eerie quality, and I wanted to express it in that way."

Heavy, dude. We love that the unexpected -- banjos, in particular -- really end up making this a pretty song, though it may carry a heavy message to its singer. Fitzsimmons' voice floats over the melody where Perry's practically commanded; wouldn't this be an odd duet?

Meanwhile, this song comes on the heels of the soft-spoken Fitzsimmons' latest full-length, "The Sparrow and the Crow," originally self-released September last year, but reissued this spring after he was signed by mighty indie Downtown Records.

Fitzsimmons is preparing to depart on an extensive European tour, to depart early next month, and is plotting another North American run, dates to be determined.

Coincidentally, Perry herself is getting an acoustic makeover as her "MTV: Unplugged" performance from this summer gets a Nov. 17 released date.

On it, Perry can be heard covering Fountains of Wayne's "Hackensack" as well as a new tune "Brick by Brick."

Perry's taped episode won't air until Nov. 27 and, weirdly, won't even be on MTV: instead, it will appear on network sister channel Palladia, an offshoot high definition music channel.

William Fitzsimmons, "I Kissed A Girl" (Katy Perry cover)