Downton Abbey star Joanne Froggatt struggled to adopt a Scottish accent for her role in new movie Filth.

Froggatt won the role of vulnerable widow Mary opposite James MCAvoy's corrupt Scottish policeman in the film adaptation of Irvine Welsh's book.

Director Jon Baird gave Froggatt the choice of portraying Mary as either English or Scottish and she opted for the latter - but she was soon left ruing her decision when she tried out the accent in front of her Scottish castmates.

She tells British newspaper the Daily Mail, "I said, 'Well, I'd really like to play her Scottish.' So the first day of rehearsals I was really nervous. I apologised to James and Jon - I said, 'This is really bad, but I'm going to do it and I'm really scared in front of you two.' They were both so sweet to me. I practised a lot - I was constantly talking in a Scottish accent at home and on set."