She was credited as Nils Sjoberg, keeping it schtum until now, for some reason - her people have confirmed the co-write to People.

It's unclear exactly what bit she appears on - harmonies perhaps? - but she's in the mix somewhere. It's probably not exactly what people wanted when they asked for a Taylor x Calvin song, or even a Taylor x Rihanna song (did people ask for that?), but oh well, it's technically here nonetheless.

Ex-beau Harris took to Twitter to confirm the news, calling her an "amazing lyric writer" before stoking the Twitter beef/calling her out.