It took filmmaker Jonathan Glazer ten years to make “Under the Skin”, the alien hitchhiker thriller which premiered Monday night at the Toronto Film Festival, and for star Scarlett Johansson, the “Sexy Beast” director was constantly orbiting new ideas.

“When I first read a version of (the script), it was almost about this couple together trying to blend into the community,” she said on Monday at the Variety Studio. “It was a very different story.”

Shot on location in Glasgow and the Scottish Highlands, “Under the Skin” is based on the novel by Michel Faber and tells the story of an alien seductress who preys on young men in Scotland. Johansson spends much of the film in the nude, including one extended full frontal scene watching herself in a mirror, in what is undoubtedly the most revealing role of her career.

“There was this challenge of having to abandon all of these normal human instincts we have,” the actress said of her character. “Our doubts and fears and judgements and start from the very beginning and have a very pure intention.”

Glazer, who admittedly took his time to find the “right D.N.A.” for the project, explained: “You’re trying to find a blend of form of content, some of it you can’t predict until the day you film them.”

“It was a very abstract beginning for the first couple of weeks until it found its heartbeat,” Johansson added with a laugh.

The actress’ nude scenes come more than a year after naked photos of Johansson leaked on the Web, which led to an F.B.I. probe and eventual arrest of two phone hackers.

“Under the Skin,” acquired by A24 on Tuesday morning, is one of two projects the “Avengers” starlet is promoting while in Toronto. The other, Joseph Gordon-Levitt’s “Don Jon,” premieres Tuesday night.

“The character I play in ‘Don Jon’ is very staid in her opinions and her ideals,” she explained. “Where is this character (‘Under the Skin’) is much more of a metamorphosis, it’s a transformation.”