Notable Role: Katie in Fruitvale (2013)
The American actress is best known for her supporting role in The Help as Elizabeth Leefolt—you know, the crazy lady who hits her kid—but that will soon be overshadowed by one simple fact: she's a part of the hottest property out of Sundance this year, Fruitvale.
And it doesn't just end with the critical praise. The film, which recounts the true story of Oscar Grant (played by Michael B. Jordan), a young father who was shot to death by Oakland, CA police in 2008, was picked up by The Weinstein Company. In other words, O'Reilly is going to be impossible to ignore.