Jessica Jung ( Korean name : Jung Su-yeon ; Hangul : ì ì ì -- ; Hanja : é ç å ; born April 18 , 1989 ) , better known by her stage name Jessica , is an American singer , dancer , and a musical theater \/ television actress . Jessica Jung ( Korean name : Jung Su-yeon ; ; Hanja : é ç å ; born April 18 , 1989 ) , better known by her first name Jessica , is an American singer , dancer , actress and model .