f(x) celebrated the group's 3rd anniversary since debut, thanking fans for their support.

Krystal posted to me2day on September 5 KST: "Today, [f(x)] turns 3! Hehe. We're old now. Please be with us until we're old. Bbooing bbooing," along with the photo below.

Victoria also posted on her me2day, "f(x)'s 3rd anniversary, congrats congrats. Good job to the members, who've worked hard until now. Let's love each other more in the future, fighting. Thank you to all those of you who support us always! Stay with us in the future too."

Rapper Amber tweeted, "Everyone, thank you so much for spending the last 3 years with us!! Vic-mom, puppy-Lulu, princess-Soojung, little-brother-Ssul, I love you," while Sulli wrote on me2day, "Everyone~ let's be happy until we turn 100~~^^."

f(x) debuted with "Lachata" back in 2009.

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Source: Krystal's me2day; Victoria's me2day; Amber's Twitter; Sulli's me2day