2. Jessica Chastain
Jessica Chastain had an absolutely ridiculous 2011, starring in Take Shelter, Coriolanus, The Tree of Life, The Help, Wilde Salome and Texas Killing Fields, with each earning her a solid amount of acclaim, most prominently a Best Supporting Actress Oscar nomination for The Help. Though it'd be difficult to expect her to compete with that immense slate this year, she turned in two great performances that made sure her momentum kept going, firstly as Maggie Beauford in John Hillcoat's crime thriller Lawless, and then more notably as CIA agent Maya in Kathryn Bigelow's outstanding Zero Dark Thirty, for which she is already being pipped for Oscar glory. As the doggedly determined agent dead-set on taking down Osama Bin Laden, Chastain is a revelation, and given that she doesn't exactly have a lot to work with - as we learn very little about her character's personal life - it's all the more impressive that she manages to bring the character to life. Her frustration at the various failures and then her final catharsis at the climax makes for a riveting experience, and she helps to guide us through the web of political machinations over the gruelling 158-minute runtime. For 2013, Chastain is starring in horror film Mama, and also a two-part drama called The Disappearance of Eleanor Rigby in which she stars opposite James McAvoy.