Kara Wai Ying-hung says she feels guilty about her late discovery of her mother's struggle with Alzheimer's disease.

"My mother showed the early-stage symptoms in her 50s, an age seemingly too young to develop the disease. I didn't realize it in time and had been rude and careless to her."

With her career spanning 40 years, Wai is one of the icons in the martial arts genre in Hong Kong cinemas. The first recipient of the Hong Kong Academy Award for best actress, Wai has acted in about 150 movies and TV series.

To make amends for her ignorance, the award-winning actress has chosen to make a film centering on the disease to raise the public awareness and promote social care of the elderly.

Happiness, which will open across China on Friday, has received wide attention at several international film events, such as the 39th Asian-American International Film Festival held last month in New York.

At the 7th Macao International Movie Festival, Wai and Carlos Chan, respectively, won the best actress and best supporting actor awards for their close-to-life performance.

Depicted by Wai as a twisted reflection of her life, the bittersweet tale chronicles an unlikely friendship between a lonely young man and his landlord, an elderly woman in the early stage of Alzheimer's.

Chan, a Hong Kong singer-actor known for the 2014 HIV/AIDS-themed movie For Love, We Can, stars as the young man, who turns from an uncooperative tenant to a caring friend.

Wai reveals that her character's physical features, with gray hair and clumsy gestures, are based on her mother, who was finally diagnosed with the illness in her 70s and is now 91.

"I owe my mother an apology," says Wai.

Wai's mother became bad-tempered and began to lose her memory when she was in her 50s. However, the signs were ignored by the then busy actress who simply saw the increasingly difficult relationship as a generational gap.

"The conflicts and squabbles in the movie were situations that I've experienced."

Once the only money-earner in family, Wai's mother peddled goods on Hong Kong streets to raise Wai and her siblings. Wai tapped into the showbiz circle at 14 and has tasted the ups and downs of the Hong Kong film industry.

"Now I'm still living with my mother, who's my biggest support. I hope people who watch Happiness will care more about the elderly at home," says the 56-year-old, who has switched to indie titles in recent years.

Latest statistics reported by the domestic media show that China has the world's largest population of Alzheimer's patients, reaching 10 million by the end of last year.

But the world's second-largest movie market, with an annual output north of 600 movies last year, has very few big-screen productions reflecting the group.

Last year, a similar-themed movie The Song of Cotton garnered limited attention amid the commercial genres that dominate the market.

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