4. Natalie Portman - Leon
If you've only ever seen Natalie Portman in the Star Wars prequels you'd be forgiven for thinking that she possesses a complete lack of talent - fortunately her filmography includes a few great performances which prove that she isn't made entirely out of wood. One of these great performances was her first, when she appeared in Luc Besson's Leon as a 12-year-old girl taken under the wings of a hitman (Jean Reno) after her parents are massacred by corrupt policemen. Portman was fortunate enough to collaborate with Besson back when he was capable of making great movies, and her combination of determination and vulnerability is perfectly pitched. Not afraid to go from blockbuster fare like Thor to art house production including Terrence Malick's disappointing Knight Of Cups, her standout performance can be seen in Darren Aronofsky's Black Swan, an award-winning turn about a ballerina slowly losing the plot.