Jennifer Hudson – Dreamgirls

Prior to her casting in Dreamgirls, Jennifer Hudson was best known for her appearance on Season 3 of the hit reality TV competition series American Idol. In spite of her seventh place finish, Hudson must have left quite an impression as she would later be cast in the Oscar-winning film. Hudson would play the role of Effie White, one of the titular Dreamgirls. She delivered quite a memorable performance in a film loaded with star power thanks to the likes of Beyoncé, Jamie Foxx, and Eddie Murphy. It's no easy feat to be a relative unknown and outshine co-stars like that, but Hudson did it with ease, earning herself an Oscar for Best Supporting Actress at the 2007 Academy Awards.