It all began when Perry allegedly hired out all of T.Swift's dancers in the middle of her tour, and it has been escalating ever since. Rumor has it Swift's hit, "Bad Blood," is about Perry, while the "I Kissed a Girl" singer has thrown Calvin Harris' girlfriend some shade via Twitter.
"Watch out for the Regina George in sheep's clothing..." the singer tweeted last fall.
Since then, the feud has only gotten worse, with both singers refusing to outright name each other in their subtle jabs but making it equally as obvious that they're directly referring to the other. Finally, Perry has made it very clear that she harbors no warmth toward the "Style" crooner.
Perry was caught earlier this week following Instagram account "Slutty Taylor Swift." Someone named Dinah owns the account, and the page is filled with random selfies and other pictures that have nothing to do with T.Swift. Perhaps Perry is just following the account because of the profile name, or maybe she's friends with Dinah.