An excellent chance to see one of Alfred Hitchcock's most perfectly realised films, with the bonus being that this is a 35mm screening. This is part of an Ingrid Bergman Selectrospective at the Prince Charles and you can find the full details of that short season here.
Chicago Reader review:
'The Hitchcock classic of 1946, with Cary Grant as a charming and unscrupulous government agent and Ingrid Bergman as a woman of low repute whom he morally blackmails into marrying a Nazi leader (Claude Rains, in a performance that makes a sad little boy of him). The virtuoso sequences—the long kiss, the crane shot into the door key—are justly famous, yet the film's real brilliance is in its subtle and detailed portrayal of infinitely perverse relationships. The concluding shot transforms Rains from villain to victim with a disturbingly cool, tragic force.'
Here (and above) is the trailer.