Yalitza Aparicio told a lie to land the lead role in Alfonso Cuaron's auto-biographical film about a domestic worker in 1970s Mexico.

How she got the part at all was extraordinary. Having never acted before, Aparicio, a then 22 year-old student, had every intention of becoming a teacher. But in a twist of fate, her theatrical sister was invited to a mysterious audition. Being pregnant and unable to perform, she pressed Aparicio to go instead. "My sister thinks that I’m shy and don’t speak that much."

But she was also curious – there had never been a casting in their hometown before. To land the role, Aparicio was not only required to speak, but also to swim.  

A year before, Cuaron had been scouring the country for someone with the likeness of his family's maid who he adored and wanted to do a film about. The search ended with Aparicio, whose likeness was uncanny. "My life was similar," said Aparicio, "We were both poor, and we both wanted to go to Mexico City to improve our family's lives. [My mother] is still a domestic worker." 

The film reaches a dramatic climax when Cleo walks into the pounding waves, risking her life to save the children she looks after. It was only a couple of days before the scene was shot that Aparicio revealed the lie she had told to get the part: “[The producers] had asked me if I knew how to swim and I had said yes. But that wasn’t true. I never imagined that this scene would take place in an ocean. But once we started shooting, the only thing I had in my mind was the same instinct any Mom would have, that you’d do anything for your children, and that’s how I was able to flow along with the scene."

Set nearly 50 years ago, the film resonates for Hong Kongers because of the enduring image of women working and living in someone else's home. Women who are there, but not there. Who are relied upon and sometimes loved, but often ignored and distanced.

This deeply personal portrayal received three awards at this year's Oscars, but critics have noted the preponderance of socially liberal filmmakers like Cuaron to reduce working women to forbearing heroines devoid of personality. But this was clearly intentional. 

In one heart-breaking scene, Cleo's waters break and she is rushed to hospital. Cuaron's grandmother is asked Cleo's middle name, age and date of birth and is tearfully unable to answer. Cuaron's father who is a doctor at the hospital comforts Cleo in the lift, but chooses not to be there for the delivery. 

They are not bad people – her grandmother escorts her through a massacre to get her to the hospital – but, in contrast to Cleo, they are too consumed with their own complex lives for understanding or empathy. The asymmetry of someone living under the same roof who knows you intimately, but of whom you know nothing, is the tragedy the film exposes.  

Having rescued the children from the waves, the family sob in embrace with Cleo at the centre. When they return home, Cleo's heroism is vaguely mentioned before the television comes on. Linen in hand, she walks gently out of sight.  

The structure of domestic working arrangements in Mexico, Hong Kong and other parts of the world is what it is. But there are heroes in our homes with stories of their own; we just need to see them, and hear them.

Written by Simon Holliday