The relationship between heart-to-heart friends. Liu Yiyun,1born in Los Angeles, California, USA on September 8th, 1992, is a Chinese-American female singer and a member of Korean female singing group f(x). Liu Yiyun can make a MV and invite 2 1 top singers to help make a guest appearance; SM's top singer Tae-yeon can only be resident; Meng Jia of MissA, Rodman of Got7, Jackson Wang of got 7, Henry Lau of Superjuniorm and other love beans can only be used as background boards; Liu Yiyun regards his colleagues he met in North Korea as close friends and his teammates as inseparable family members. So the relationship is very good.