There is a shroud of mystery surrounding the track, which a lot of fans think features vocals from Taylor's younger brother, Austin, with production linked to the pseudonym previously attributed to Taylor in disguise (Sjöberg) on the co-write of the 2016 track "This Is What You Came For" for Calvin Harris and Rihanna.
Even more interesting is the Swiftie theory that the singer might be exacting some sweet revenge on former Big Machine boss Scott Borchetta and his partner, Scooter Braun, by releasing a cover version of a song from her back catalog that the two men now jointly own.
Fans also pointed out that 28-year-old Austin formerly used "The Dolphin Club" as his Twitter handle, based on a childhood photo of him wearing a shirt with that title on it, which, wait for it, he's wearing in the cover art for the song.
Check out the best fan theories about the cover below.
Listen to the song below.