Taylor Swift usually saves her emotions for her songs.
However, she offered some heartfelt words on Twitter on Monday to mark the special day of her close friend Selena Gomez.
"Happy 21st birthday to my friend, and the closest thing I've ever had to a sister, @selenagomez!!" Swift wrote.
[Related: Selena Gomez's Bad-Girl Moments]
Gomez's "Spring Breakers" co-star Ashley Benson also sent well wishes her way.
— Ashley Benson (@AshBenzo) July 22, 2013
Zendaya, who's followed in Gomez's footsteps as a Disney Channel star, took the time to pay the former child star a compliment.
Gomez herself posted a clip that shows her partying with pals to her tune "Birthday." The track is from "Stars Dance," the first album Gomez has recorded without her backup band, The Scene, which comes out on Tuesday.
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