On June 2nd, during KCon in France
As for Jieqiong, she has already mentioned Krystal twice in interviews.
She explained that she actually was going for a cold-chic image like Krystal's but it didn't suit her well. She tried to act pretty and it made her popular among girls, but guys don't really like that side of her.
Q: Are there any singers that you want to stand in the same stage with?
A: F(x) Krystal. Her lines are so pretty when she dances.
-ㅋㅋㅋㅋㅋSo cute
-Sohye's eye balls look like they're going to fall outㅋㅋㅋㅋㅋㅋㅋㅋㅋ
-Zhou Jieqiong is so cuteㅋㅋㅋ
-So cute.. It's indeed a visual that makes everyone turns their heads..
-Look at Yeonjung's expressions when she saw Krystalㅋㅋㅋㅋㅋㅋㅋㅋㅋㅋㅋㅋㅋㅋㅋㅋㅋㅋ
-Krystal is indeed really pretty...
-I also like Krystal so much..
-I would do the same if I was standing next to her..
-Krystal is pretty and Yeonjung's expressions when she saw Krystal is so cuteㅋㅋㅋㅋㅋ
-How could a person be that pretty...
-Kim Sohyeㅋㅋㅋㅋㅋ I would look at her the same way, thoughㅋㅋㅋ
-I might faint because our Soojung is so pretty..
-IOI is cute and Soojung is pretty..
-Jieqiong's eyes were fixed on herㅋㅋㅋ