The star ditched her trademark blonde locks in favour of a short brown bob to play Patricia Lomax, shooting in Bo'ness station in Falkirk.
The film is based on a true story and follows the life of Eric Lomax - played by War Horse's Jeremy Irvine - a British officer captured in World War II by the Japanese and sent to a Prisoner Of War camp.
From there Lomax was forced to work on the infamous 'Death Railway', which stretched from Thailand to Burma.
Years later, blighted by psychological trauma of his experiences at war and played by national treasure Colin Firth, Lomax confronts those responsible for his torture with the help and support of his wife.
The film is based on Lomax's book of the same name and is set for release in 2013.