Rainier Joseph Diaz Castillo, better known simply as Rainier Castillo (born October 21, 1985 in Quezon City, Philippines), 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. He is now a Kapatid of TV5. A freshman from AMA Computer University, he joined the reality-based artista search "StarStruck" and was linked over four female survivors during the competition: Jade Lopez, Yasmien Kurdi, Jennylyn Mercado and Sheena Halili. He was linked with Jade Lopez because during the competition Lopez had a crush on him, he was linked with Sheena Halili and was his love team on the competition but when Halili got eliminated their love team had stopped after the contest they continued to have a relationship but later called it off. Though he lost in the competition, StarStruck was his turning point for his career. This was considered the biggest thing happened to his life that provided door for more opportunities. He is visible in shows of the station such as teen-oriented shows like Click and Joyride, fantaseryes like Mulawin, Majika, Kamandag, Fantastic Man and Tasya Fantasya, comedy shows like Hokus Pokus and drama series like Maynila, Love to Love and Bakekang. He recently transferred to TV5 and signed a two year non-exclusive contract with the network, and has a new manager named Noel Ferrer (the manager of Ryan Agoncillo and many others). Rainier has also a few commercials to his credit, such as Hapee Toothpaste (one commercial as an individual and another with Angel Locsin). He also was a model for Bench FIX Salon and was in Bench's 2004 Understatement underwear fashion show in Araneta Colliseum.