They first appeared on the red carpet together at the 2008 MTV Video Music Awards.
The pair immediately became fast friends, with Taylor tweeting about how much she loves "Waking Up in Vegas" and Katy even suggesting they write a duet together.
It's no secret that Katy Perry and Taylor Swift have had some bad blood between them before and just when we thought everything had been put in the past and the girls had matured, news breaks that Katy has totally beaten out Taylor for a top spot as the most popular person on Twitter!
No way! Katy recently hit 80 million followers on Twitter which is a huge accomplishment. Obviously, her fans and many others like what she has to say on the platform whether it be funny, about her personal life or her work life.
We can't say as much for Taylor though! Taylor has 68.9 million followers, which of course is a lot but not as many as Katy. Even Justin Bieber beat Taylor with 72.9 million followers! Do you think Taylor is upset about this??
It's pretty crazy that it came down to these particular pop stars. Maybe Taylor will step up her Twitter game in 2016 and we could see a spike in her followers! It's in the hands of the Twitter sphere now!
Do you follow Katy or Taylor on Twitter? Let us know in the comments below!