Yesterday, it was revealed that Calvin Harris's co-writer on his latest smash hit 'This Is What You Came For' was none other than his ex-girlfriend Taylor Swift.

Swift contributed to the track under a pseudonym which was kept secret until now - when Harris went on an epic Twitter rant explaining why he had not spoken about the collaboration previously.

Despite their 'feud' (which we're still not convinced isn't staged), the pair have already made a pretty penny from the song, which features Rihanna on vocals.

Billboard have extensively broken down how much the song has earned to date (about $511,000), subtracted the label's fee, performance royalty fees and Rihanna's fee, added in royalties and publishing incomes and worked out how much each of them have made from the song - which was only released in April - to date.

They estimate that Harris has made approx. $354,000, while Swift has made approx. $193,000.

Not bad for one song. It's no wonder Swift is officially the highest-earning celebrity around right now.