The ladies of f(x) made their official stage debut with "LA chA TA" on the September 5, 2009 broadcast of 'Music Core.' Since then, the girls have become one of the most popular groups in all of K-pop. To thank fans, Amber took to her Instagram and wrote a sweet message.

Amber wrote, "Lucky 7!  Always thankful to all the MeUs out there who've always had our backs. But on the real though... We getting old XD Never gunna stop the grind and always gunna work hard for all you guys!!! [sic]."

Aw, what an awesome gesture by Amber!

https://www.instagram.com/p/BJ8X1B4jxnn/