Taylor Swift Wishes Selena Gomez A Happy Birthday & Calls Her 'Sister' On Twitter!

BFFs FTW!

It’s Selena Gomez’s 21st birthday today, and Taylor Swift wants the world to know!

The country crooner sent her bestie some heartfelt wishes via Twitter earlier today, calling Selenita “the closest thing I’ve ever had to a sister” while sharing a totes adorbzies photo of the two posing like mermaids:

Happy 21st birthday to my friend, and the closest thing I've ever had to a sister, @selenagomez!! pic.twitter.com/GhOgkl3kZ1

— Taylor Swift (@taylorswift13) July 22, 2013

LOVES IT!

Show ‘em how it’s done, ladies!

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[Image via Twitter.]