Anne Hathaway had to learn the "Hidden Rules of English Behaviour" for 'One Day'.

The American actress plays the part of British woman Emma in the romantic film, and shaped her character's mannerisms around what she read in her "bible", 'Watching the English: the Hidden Rules of English Behaviour', a tome all about the personality quirks of the English.

She told the UK edition of HELLO! magazine: "There's a book that became my bible. It's called 'Watching the English: The Hidden Rules of English Behaviour' and there's a chapter on British humour, which was very helpful to me.

"My character uses humour a lot - she's witty and quick and I love that in her."

One distinctly English trait which took a little longer for the 28-year-old star to master was Emma's habit of apologising for herself all the time.

She said: "My character apologises for herself a lot, which is a very British thing to do. Americans never apologise for themselves."

To get into the role, Anne also had to go to Yorkshire, Northern England, and work on both the regional dialect and learn about local customs, which she admits was hard work, and saw her practice for eight hours a day with a voice coach.

She added: "The accent didn't come easily at all and it required an enormous amount of work to get it right.

"You know how Natalie Portman worked on ballet pointe for 'Black Swan'? That was me trying to be Yorkshire!"