Hollywood actress Sigourney Weaver hopes her latest movie will help improve people's understanding of autism.

The 56-year-old said she believed the comedy Snow Cake, in which she plays a high-functioning autistic woman, would provide a new perspective on the condition.

Weaver, best-known for her roles in the Alien films, was speaking at the movie's British premiere at the Edinburgh International Film Festival last night.

She said people with autism she met while researching the film were crying out for a fresh portrayal of the condition on screen.

"Even though Rain Man was a great movie, there hasn't really been much about autism since," she said.

"I think it's going to be welcome to have another view of what it is - a young woman who lives alone, a woman who has a job - so people can get closer to how many different ways autism manifests itself."

The Marc Evans-directed film sees Weaver in the role of Linda Freeman, the mother of a teenage girl who dies in an accident on a road trip with quintessential Englishman Alex, played by Alan Rickman.

While Linda understands the loss of her daughter, she is incapable of showing any emotion.

Weaver described playing the role as an intense but rich experience and one in which she became friends with a number of people in the autism community.

She said: "I got a lot of coaching from people with autism on what not to do and how not to be, and on what to do and what to be.

"It was a great experience actually. They really were very generous to me and I really spent a lot of time in private places."

Harry Potter star Rickman said he was drawn to this latest venture because of the quality of the script.

Speaking outside the Dominion Cinema in the city's Morningside area, he said it was great to be back in Edinburgh for the festival season and he said that he had "two hats on this year" because he is also directing a play at another venue in the Scottish capital.

Edinburgh-based Harry Potter author JK Rowling was in the audience with her husband Neil for the premiere.

The writer, who lives nearby, joked that it was "lovely" to have been able to walk to the venue.