They are both young, successful and wildly popular in the world of music.
So aren't Miley Cyrus and Demi Lovato making like Taylor Swift and Lorde? Why are these stars not only distant, but full-on enemies at this point?
It goes all the way back to 2009 and a video Miley made at the time that mocked Demi and Selena Gomez.
The relationship was frosty for years after that and Lovato then stoked the feuding flames when she dissed Miley in a Tweet earlier this year.
Click around below and relive the steps that led Cyrus to the ultimate move just a few days ago: unfollowing Lovato on Twitter. We told you this was serious!