Idris Elba & Tilda Swinton On How Three Thousand Years Of Longing Differs From Their Other Projects

Actors Idris Elba and Tilda Swinton have been known for playing all sorts of fantastical characters on the big screen over the years. When it was announced that they would both be starring in the upcoming film adaptation of "Three Thousand Years of Longing," it just seemed to make sense.

The film, based on a short story by A.S. Byatt, follows a woman named Dr. Alithea Binnie (Tilda Swinton) who lives a logical life. She receives a surprise when a genie, or Djinn (Idris Elba), visits her and insists on granting three of her greatest wishes. The only problem is that this rational woman doubts he's even real in the first place, which is when their supernatural story starts to unfold.

When Swinton was approached with the role, she knew she needed to make it special. "Both Idris and I very quickly shared with George [Miller, the director] that we were both at the same stage in our work," the actress said during a recent press conference that included The List. "We wanted to do something different."

Elba wanted to approach the film in a unique way as well. "As actors, we dread being stale. We want it to be fresh a lot," he said. He and Swinton also explained exactly how making this fantasy film was much different for them than their other movies.

Idris Elba created his own accent for the film

Seeing as Idris Elba was set to play a supernatural character in "Three Thousand Years of Longing," he wanted to make sure he sounded like one, too. But no one knows exactly what a genie sounds like — so Elba decided to make it up. "I got to create an accent that before this film, didn't exist," he explained during the press conference.

While Elba pulled from various accents in order to create his foreign voice for the film, he guarantees it will be like no sound you've yet heard on the big screen. "It might sound similar to things you may have heard before," he said. "But the work that we did in order to create his voice was really exciting to me."

In fact, his character was ultimately years in the making. "We sat around a room for weeks on end — years, in fact; two years probably — kicking this around," he said.

Tilda Swinton felt free to improvise scenes

Tilda Swinton has become accustomed to playing mystical characters over the course of her career, from the White Witch in the "Chronicles of Narnia" films to a vampire in "Only Lovers Left Alive." But her role in "Three Thousand Years of Longing" was a different undertaking altogether. "The great opportunity here was to play the human, was to play the mortal in the face of the immortal," the actress said. "That was definitely a fresh road for me."

Unlike any other human, however, her analytical character isn't interested in having the djinn grant her greatest wishes. She suspects it's a trap.

Even so, Swinton felt all sorts of magic whenever she stepped foot on set. "We still felt free at the last minute to try fresh things," she said. "Even though we'd been making decisions for months and coming to choices, we still felt very open and free to bat it back and forwards in different ways through the takes."

Because of that, Elba and Swinton had all sorts of creative freedom to make the characters even more of their own — into something that audiences are sure not to have seen from each of them before.

"Three Thousand Years of Longing" hits theaters on Friday, August 26.