Claire Foy had the support of a voice coach to master her American accent for her role in 'The Girl in the Spider's Web'.

Claire Foy

Claire Foy

The 34-year-old English actress plays Lisbeth Salander in the thriller - a role previously portrayed by Rooney Mara and Noomi Rapace - has always struggled to master a Yankee twang but she enlisted the help of an expert to get her voice spot on for this project.

Appearing on 'The Tonight Show Starring Jimmy Fallon', Claire said: "I've never done it with a coach I've always sort of done it badly. This time I was more confident about it. When you're doing an accent sometimes some weird thing comes out of your mouth, it just makes funny shapes."

The movie is based on the book of the same name by David Lagercrantz, which features the characters created in the Millennium series by late author Stieg Larsson.

Claire read Larsson's original trilogy when she was in her 20s and was blown away by the character of Lisbeth and she jumped at the chance to take on the part even though two other actresses had already brought her to the big screen.

She said: "I read them when I was about 23. I never read a character like that and I was a young woman reading a character like that and it was an amazing thing. I'd seen those performances of Noomi and Rooney - the best names ever - and I just thought it was incredible. So once I'd heard about it and really reading the books I couldn't not do it. It's a real thriller."