Sara is a step forward for Charlene Choi's acting career

She is still better known as one half of Canto-pop duo Twins, who are set to celebrate their 15th anniversary with a range of projects later this year, but Charlene Choi Cheuk-yin's career as an actress has gained serious traction of late.

In her latest film Sara, 32-year-old Choi plays the title role of a sexual abuse victim who has an affair with a much older man (played by Simon Yam Tat-wah) during her adolescence. Later, she starts working as an investigative journalist, and stumbles across the story of a young prostitute (Sunadcha Tadrabiab) in Thailand.

This is the first title released by the production company, Hong Kong Film, which was set up by Chapman To Man-chat in 2013 with the aim of making "purely Hong Kong films that can't be sold to mainland China", To told the Post last year.

As its lead actress, Choi, who was born in Canada and moved to Hong Kong at the age of three, is less concerned about the film's identity.

"I don't mind where my films are released," she says. "The internet reaches everyone; even if you make a film that tanks at the box office, it doesn't mean that people haven't seen it. So if a project gives me a chance to express myself, I'll do it."

Sara is one such project. In 2013, Choi, To and singer-actress Fiona Sit Hoi-kei posed nude - except for the signboards they held up - for an anti-slavery campaign organised by the charity Liberty Asia.