Pop music's biggest beef has officially been squashed – after year's of mutual disdain, Katy Perry and Taylor Swift no longer have any bad blood.

Swift took to Instagram on Tuesday to reveal Perry extended a literal olive branch to her via the mail.

Perry's package included a semi-legible card which reads, "Hey old friend, I've been doing some reflecting on past miscommunications and ... feelings between us. I really want to clear the air ... I'm deeply sorry ... "

The former – and, now, current – friends notoriously began feuding back in 2013 when Perry allegedly poached Swift's backup dancers for her tour.

Since then, the two took not-so-subtle shots at each other in songs like Swift's "Bad Blood" and Perry's "Swish Swish."

It's a big day for Taylor, not only did she squash a beef but her new tour kicks off tonight.

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