SINGAPORE - In popular Western mythology, djinns, or genies, are famous for granting wishes, as depicted in the One Thousand And One Nights collection of tales, which have been adapted into numerous movies and television shows.

So when British actor Idris Elba agreed to play one in the fantasy film Three Thousand Years Of Longing, which opens in cinemas on Thursday, he made a choice.

The 49-year-old says he wanted to do the unexpected, even though the djinn enters the story in the most traditional way possible - by the breaking of a spell that has imprisoned him in a bottle for centuries.

"It was really important to me to veer away from anything that we may have seen before, because I think this character's journey is believable only if we feel like we have never seen anything like this," he adds.

Audiences have been so strongly conditioned by media depictions of djinns as clowns, tricksters and wish-givers, Elba says.

"The audience is gonna go, 'Oh, okay, haha, tell me a joke. Do the wish thing. You know, do the magic thing.'"

He was speaking at an online press conference with his co-star, British actress Tilda Swinton, and Australian writer-director George Miller.

With the veteran film-maker, Elba says he found a way to subvert expectations. "Quite cleverly, George makes you want to ask, 'Is he real or isn't he real?' And that's the device that we end up with at the end of the film."

Swinton, 61, plays Dr Alithea Binnie, a scholar who lives by the rules of evidence and rationality. While in Istanbul for a conference, she finds the bottle that releases the djinn. In her hotel room, he tells her tales of his life in the royal courts of the past, up to the point of his imprisonment in the bottle.

Three Thousand Years Of Longing is adapted from a 1994 short story, The Djinn In The Nightingale's Eye, by British author A.S. Byatt.

Miller, 77, who helmed the violent action blockbuster Mad Max: Fury Road (2015), as well as the family movies Babe: Pig In The City (1998) and animated adventure Happy Feet (2006), says fairy tales interest him because they are "paradoxical" - viewers from one culture will interpret the stories in the same way, but within the conformity, private meanings can flourish.

"The symbolism can be read by each person experiencing the story, but at the same time, they are sharing meanings with the collective," he says.

Swinton was drawn to the role of Alithea because the character of the fussy academic was a "departure" for her. She says she has tended to be cast as the immortal, like in Doctor Strange (2015), where she plays the sorcerer The Ancient One.

She likes how Alithea resembles a stereotype - the stuffy older woman who finds something awakening within her - and wanted the challenge of giving that character life and nuance.

"Alithea made her decision to live alone, to not have desire and to be intellectual and rational, to be above emotion," she says.

"There are all sorts of ways of that being a slightly scary stereotype, and we were aware of that. And just to try and negotiate that was really an interesting sort of daily workout for all of us," she says.

Three Thousand Years Of Longing opens in cinemas on Thursday.