On the August 21 episode of 'Radio Star', Sulli was asked to choose the prettiest female idols in the industry. She chose Taeyeon as #1 and then chose IU as #2. After hearing IU, Kim Gu Ra then spoke up to say, "Isn't the relationship between IU and SM bad?" The question made Sulli, Krystal, and Kyuhyun burst out into laughter.

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Kyuhyun answered, "It's not that she has a bad relationship with SM", and Kim Gu Ra said, "Ah, it's that she has a bad relationship with Super Junior", sending the studio into laughter again.