Taylor Swift brings her albums back to Spotify, Pandora, Google Play

Some people are theorizing that Swift timed the release of her music on Spotify to undercut the attention around Perry's new album.

Taylor Swift may sing about "never ever ever getting back together" when it comes to ex-boyfriends, but lucky for fans, she's willing to make nice with streaming sites again. Spotify said in a statement: "We can confirm that Taylor Swift's entire back catalogue is now available on Spotify for her millions of fans to enjoy". The following year she announced she would withhold "1989" from Apple Music because of its policy of not paying artists and rights holders for music streamed during a three-month free trial period.

@roarsus wrote on Twitter: "I think we all can agree Taylor Swift is the most immature artist of all time".

In a pop star gut punch heard 'round the world, Taylor Swift did her best to overshadow Katy Perry's release of Witness tonight. You do something and there's going to be a reaction. It was this dispute that made her pull all her music from streaming services in the first place, actually.

She continued: "But, what I wanna say is that I'm ready for that B.S.to be done".

As probably the biggest star to adamantly boycott the new technology, Swift's about-face could have wider implications for the music industry at large. Swift hasn't released a new album since 1989 ― an unusually long hiatus, indicating that a new record could be in the works.

Perry has spoken out about the tension with her former friend. "That's so messed up", she added.

Last month, Perry told The Late Late Show host James Corden: "That's true, there is a situation".

She has taken that service to task, too. "Especially when someone tries to assassinate my character with little girls", she sniped. "She started it and it's time for her to finish it".