Executive Producer, Author, and Screenwriter Ian McEwan stated to an audience back in 2014 that he wanted Saoirse Ronan to play Florence Ponting.
Saoirse Ronan's second role in a movie adapted from a novel by Ian McEwan. The first being Atonement (2007).
Carey Mulligan was previously attached to portray Florence Ponting when Sam Mendes was set to direct.
Saoirse Ronan said she originally wanted to play Florence Ponting back when the film was first in production, but was too young for the role.