A Thai film about a young man caring for his dying grandmother as he vies for her fortune has struck a chord in South East Asia, where TikTokers' teary responses are going viral.

How to Make Millions Before Grandma Dies has topped box offices across the region since it was released in April.

The film follows M, who is plotting to win an inheritance from his cancer-stricken grandmother, but begins to question his motives as he grows closer to her.

The story appears to have deeply resonated with moviegoers, who have been sharing emotional videos of themselves before and after watching the film.

"Running over to hug my grandma now! Exceptionally touching film... This movie hit even harder because it reminded me of my own relationship with my grandma," wrote a TikTok user ianjeevan.

Young people have posted online about how they were especially moved by scenes where the grandmother was in pain and kept calling out for her late parents to “take [me] with them”.

"I cried so much that all of my make up was gone after the movie," one TikToker said, referring to those scenes.

Another, diariesofswan, said: "After the movie, cry. Just cry, when you miss someone, whom you can't even hug or hear their voice anymore."

The movie was inspired by scriptwriter Thodsapon Thiptinnakorn's relationship with his grandmother. And it is director Pat Boonnitipat's first feature film. He told the BBC he was "really surprised" by the overwhelming response, and that the movie's appeal lay in its ability to tap into the "conflicted" nature of family relationships.

Part-dark comedy and part-tear-jerker, the story revolves around a dysfunctional family that uses the matriarch’s diagnosis to scheme for her fortune.

M, played by 24-year-old singer-actor Putthipong Assaratanakul, is one of them. The college dropout moves in with his ailing grandmother, ostensibly to help care for her.

Well aware of her family's intentions, the matriarch – M’s grandmother, played by Usha Seamkhum – nevertheless loves and accepts her children.

Ms Seamkhum, 78, has recieved rave reviews for her acting debut. Film critic James Marsh called her “absolutely sensational” as the “figurehead of this morally questionable rabble”.

Other than her, the characters are far from likeable - Mr Marsh described them as "loathsome" even. Yet this tale of scheming family versus loveable grandmother appears to have touched many.

"We love them, we also hate them, but we also have to live with them. And sometimes we neglect them. Perhaps this movie reflects the many, many angles of that complexity of a big family," director Pat Boonnitipat said.

Some of those who watched the film said it reminded them to spend time with their loved ones, while others said it rekindled memories of their grandparents or parents who had died.

One TikTok user advised people to "bring many boxes of tissue if you are going to watch this movie". Some clips online show staff handing out tissues to moviegoers as they walk into the cinema.

Malaysia's largest cinema GSC has marketed the film as a must-watch for people who "need a good cry", while SM Cinema in the Philippines had staff giving out tissues outside theatres showing the film.

Ticket sales in Thailand crossed 250m baht ($6.9m, £5.3m) in the first 14 days of its release, making it 11th highest grossing Thai film.

It has also become the most successful Asian movie to hit screens in Indonesia, and the highest-grossing Thai movie in Singapore and Malaysia.