Dakota Fanning's performance in Vicious was inspired by a real-life experience

The Hollywood star told Extra: "The character that I play, Polly, receives a package from a mysterious visitor, and chaos ensues. I think it's really a pure horror film, and then at its centre it's like a story of this woman who's in this psychological battle within herself, with her own thoughts, with her own mind."

Dakota subsequently explained how a "lucid dream" influenced her performance in the movie.

She said: "I once had this really lucid dream that when I woke up in the morning, I for five minutes didn't know if the dream had really happened or not, like, genuinely. And I was like, 'I've lost my mind.' And I think that's sort of the place that we're meeting Polly at. And it just kind of goes from there."

Dakota found the role to be emotionally taxing.

The actress explained that she spent hours crying on set every day for the movie, and that the experience left her feeling emotionally exhausted.

She explained: "You're crying for 12 hours a day pretty much most of the time, but I've always been an actor that's had to like dip in and out. Like, I can't hold it for a whole day, you know, like, I have to be able to laugh."

Dakota actually cherished leaving the set and putting her work behind her each day.

The actress - who is the older sister of fellow film star Elle Fanning - explained that she enjoyed escaping the emotionally-draining work.

Dakota shared: "There's no better feeling than being done at the end of the day and then going home. And for me, it's, like, getting in the bathtub and then watching my shows on my iPad in the bed. Then you just like wait for that moment and it's so nice."