Ronan plays the part of a 14-year old killing machine.
Ronan's father in the movie is ex CIA. (Eric Bana)
In the Joe Wright movie, Ronan begins to enjoy a more conventional life after a French family take her under their wing and look after her.
Cate Blanchett also stars in the movie.
Filming began a few weeks ago in France and is due to continue on to Germany and the U.K.
It is due to be released in 2011.
Joe Wright also directed Atonement which put Ronan on the map.
We look forward to seeing this side of Ronan.