Rumours had been circulating online that she was the lyricist behind This Is What You Came For, which features Rihanna.
Swift's representative confirmed it to People magazine, which the DJ retweeted from his official account.
He wrote: "Amazing lyric writer and she smashed it as usual."
Swift wrote the song under the pseudonym Nils Sjoberg.
Perhaps annoyed at the way the story about their collaboration came out and was told, the DJ then posted a string of tweets about Swift and her team.
The break-up of Taylor and Calvin has dominated headlines around the world.
Since then, paparazzi has followed Taylor and her apparent new boyfriend - Tom Hiddleston.
The pair have been pictured everywhere together, but has led to speculation and conspiracy theories that their relationship is for a new music video.
Taylor's Twitter is quiet so far and she's given no reaction to Calvin's comments.