CANNES •Robert De Niro famously gained 27kg to play boxer Jake LaMotta in Raging Bull (1980) while Leonardo DiCaprio slept in an animal carcass and ate raw bison liver in The Revenant (2015).
But few actors have gone as far as to live on the streets to research their roles. That is what Singaporean director K. Rajagopal asked of the star of A Yellow Bird, his film that touches on some of the country's most sensitive issues of race, migration and sex.
Television actor Sivakumar Palakrishnan spent his weekends living rough on the streets of Little India.
The arthouse movie, which premiered on Wednesday at the Cannes Film Festival, follows an ethnic Indian man trying to rebuild his life and family after a spell in prison.
Rajagopal said: "I made him go out and live and sleep in the streets because he doesn't come from that side of the tracks. It was quite tough for him, but he did it. I wanted a fresh response, for him to feel what it was really like to be homeless."
The film, which is showing in the Critics' Week section of the festival, also touches on the "simmering tensions beneath the skin" of Singapore's multiracial melting pot.
Struggling ex-convict Siva has to sleep on the kitchen floor with his mother because she has rented out the bedroom of her tiny apartment to mainland Chinese migrants.
"This is not unusual," the director said. "People rent rooms to foreigners to make money to pay the rent."
It also touches on another taboo subject - interracial relationships - throwing Siva together with a Chinese migrant mother (Huang Lu) who is forced into prostitution.
Rajagopal said of his portrayal of his homeland: "I was going for the underbelly, the marginal, because Singapore has a reputation for being modern and ordered. But there is this other side. It is a reality too."
Perhaps the most sensitive subject the film deals with is the place of the country's Indian minority.
He said: "I am seen as a foreigner in my own country. When I get into a tax office, they ask me, 'Where are you from?' I was born here. But any Indian is not supposed to be Singaporean but foreign. It affects your whole personal, emotional space. Both Indians and Chinese are of migrant stock and yet we are not very accepting of the new influx. We say these new Chinese are not like the Singaporean Chinese. I wanted to reflect that, which is also now a global issue with migration."