Yukiko is a minor charater of the movie, Perfect Blue.
Yukiko is a co-singer of Mima in the pop group CHAM!, along with Rei, and stayed in the group for three years. When Mima has her last performance, Yukiko is the one who annouces Mima's departure because she was too upset to say about it. After Mima leaves CHAM! the two singers become more popular and they end up on the best singing group charts.
Yukiko seems to care little about Mima's new career; this is evident during one scene in the film, where she talks to Rei about Mima's appoinment with Murno, the "porn" photographer, and says that Mima likes to take her clothes off.