Girl's Day celebrated the 4th anniversary since the group debuted on July 9, 2010 with 'Girl's Day Party 1'!

Hyeri tweeted, "Our unnies, I love you today, tomorrow, and even the next day with no change. �Just like we were together every day for four years, let's be together forever. �I love you~~~"

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Yura wrote, "So delicious. �Going to eat deliciously since it's our fourth anniversary~~~ (Hyeri came out like this but she told me to put it up)," which was quoted by Hyeri, who added, "Sojin looks funnier than I do kekekeke..."

Minah posted, "I also ate cake TT I must not have eaten it deliciously as they didn't take a picture of me... That's a shame, but I'm really grateful for the cake. �Today's song is really touching."

Congratulations to the girls!

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� ????_?? (@Girls_Day_Hyeri) July 8, 2014

"@Girls_Day_Yura: ????? 4???? ???????~~~~?????? (??????????? ???? ?????) pic.twitter.com/Ku2xrWrhSt" ??? ????? ? ??????????????????????????????

� ????_?? (@Girls_Day_Hyeri) July 8, 2014

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� MiNA (@Girls_Day_Minah) July 8, 2014