They may or may not be dating, but Shawn Mendes and Fifth Harmony's Camila Cabello will go public with what sounds like an extremely promising new duet.

The "Stitches" singer and the girl group member revealed a teaser of their upcoming duet, "I Know What You Did Last Summer," that sees the duo harmonizing over some acoustic guitar strumming. (And by the way, the song has nothing to do with the "I Know What You Did Last Summer," the new duet between Jacob Whitesides and Kelly Rowland).

Also notably, "I Know What You Did Last Summer" seems like we could be hearing Camila embrace a more folky-pop song, which will be a big contrast to the hip hop- and dance-inspired pop 5H creates.

No set date for the release of "I Know What You Did Last Summer," but the cut is set to be included on a repackaged version of Mendes' No. 1 album Handwritten, titled Handwritten Revisited, which drops on November 20.