Director Joe Wright had wanted Keira Knightley to play the role of Briony in her late teens, but Knightley immediately liked the character of Cecilia, and also wanted to get away from playing girls on the brink of womanhood and play a more mature character for once.
Only eight U.K. military ambulances from World War II remain, and this movie made use of them all.
The green dress which Keira Knightley wore in this movie has been named "the best of all time" by InStyle Magazine, exceeding some classics as Audrey Hepburn's little black dress in Desayuno con diamantes (1961), Marilyn Monroe's white dress in La tentación vive arriba (1955) or Vivien Leigh's red dress from Lo que el viento se llevó (1939).
Saoirse Ronan was only 12 years old when this production began shooting and turned 13 by the time she received her first Oscar nomination.