15/11/2011 09:39 GMT | Updated 15/01/2012 05:12 GMT

Michelle Williams On Screen Icon Marilyn Monroe: 'I Think Of Her As A Friend'

Michelle Williams has revealed she thinks of Marilyn Monroe as "a friend".

The Brokeback Mountain star admitted it was daunting taking on the role of the Hollywood star in My Week With Marilyn, so she tried to play down the character in her mind.

Williams said: "How could anyone not be [nervous playing Marilyn]? I kind of ignored it and tried to make her - in my own mind - not a famous person, more like a friend than an icon."

The 31-year-old actress revealed she watched Marilyn's films over and over to help her get into character.

She said: "I read anything and everything that I could get my hands on. The most useful thing was to watch her movies over and over again, to have them in my ears, to make them play like a screen in my mind."

And Williams still counts the films among her favourites, despite watching them over and over again.

She said: "I am very fond of The Prince and the Showgirl still - I can't count the number of times I have seen it! Of course Some Like It Hot and I have special affection for The Misfits as it was a treasured opportunity for her to take on a dramatic role."

My Week With Marilyn is out on 25 November. Watch the trailer below: