The 71-year-old actress said there was a "charming" quality about her character, Emily Walters, that made her want to portray her onscreen, reported Femalefirst.
"This character of an older woman, who's a mess, that excited me. She doesn't own up to her mistakes but she's friendly and charming. Then there's this amazing moment when she looks through her binoculars and sees this man, and her life changes forever," Keaton told TimeOut magazine.
The film directed by Joel Hopkins also features Brendan Gleeson, Lesley Manville, Jason Watkins and James Norton.
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