On October 1, f(x)'s Luna updated her personal me2day account to show off her close relationship with actress Kim Hae Sook.

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She wrote, "Mentor Kim Hae Sook invited me to her movie 'Tough as Iron' so I went with my family and friends.  I'm very grateful for my mentor who always takes care of me warmheartedly.  After watching the movie, I promised myself to be better to my parents.  Everyone, watch 'Tough as Iron' and be good to your parents!"

In the pictures, Kim Hae Sook and Luna indeed look very close.  Kim Hae Sook looks like she is about to kiss Luna on the cheek in a loving and motherly manner.  They are also embracing in the right picture to show off their close relationship.  

Netizens showed surprise at how close the two of them appeared and also expressed some jealousy towards their relationship.