Rainier Joseph Diaz Castillo, better known simply as Rainier Castillo, is a Filipino actor, singer, model, and dancer. His father lives in Winnipeg, Manitoba, Canada. He is known for his "killer smile" and one-trick pony of identified with his F4 hairstyle of Jerry Yan. He made it as one of the Final Four in the first season of StarStruck, though he eventually lost the title of Ultimate StarStruck Male Survivor to Mark Herras. He is a former star of GMA Network, now a Kapatid of TV5 then in 2014, Castillo went back to Kapuso Network.