f(x)'s new single, "4 Walls," which we have been waiting for practically forever now, was finally released yesterday. 

Fans who have been f(x)-deprived quite a while, must have listened to the song over and over! Even listeners who may not have been fans of f(x) to begin with probably fell in love with the sleekly modern, contemporary electronica sound! 

SEE ALSO: Actress Kim Ji Won revealed to have purchased a building for 6.3 billion KRW (4.6 million USD)

Let's celebrate the girls' return into the K-Pop scene and congratulate them on achieving 1 million in such a short amount of time!