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.

SEE ALSO: Zico & BLACKPINK's Jennie hang out at the 'SPOT!' in official MV

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.