Taylor and Katy go *way back* when TS said someone she thought was her friend was being nasty behind her back and then some of her tour dancers stepped back and joined Katy's tour. Then everyone assumed Bad Blood was a song about KP. Then KP called out for the "Regina George in sheep's clothing", which everyone assumed was TS. Then Bad Blood was announced as a single and Ellie Goulding, KP's friend, as a guest appearance, to which - people assume - KP twitted about how time is the truth teller. TS has been asked if it's about KP and she just goes around in circles without answering, but... oh, the facts...
So yeah, there's a feud going on lol they probably won't be seen anywhere near each other these days