The duo revealed on social media late Thursday that they had collaborated on a song called "I Don't Wanna Live Forever," for the upcoming Fifty Shades Darker soundtrack.
Shortly after the song was released on iTunes it went to No. 1 and Swift couldn't help but acknowledge how quickly they hit the top spot.
"Well that escalated quickly. @jackantonoff @zayn @sam_dew," Swift posted on Instagram with a photo of their song in the No. 1 slot.