"Michelle Williams has been asked to portray Marilyn Monroe on the big screen. The ‘Brokeback Mountain’ actress has been lined up to play tragic screen icon Marilyn in movie ‘My Week With Marilyn’ – which will focus on the making of her 1957 film ‘The Prince And The Showgirl’ with Laurence Olivier.
Although Michelle has been offered the part by director Simon Curtis and producer David Parfitt, the 29-year-old has asked for some time decide whether or not the part is right for her.
Simon is due to meet with her in 10 days to receive her decision. If she accepts the role, Michelle will start filming in London in June.
Ryan Gosling with Michelle Williams while filming "Blue Valentine" (2010).The storyline – which was written by Adrian Hodges and is backed by BBC Films – is based on a diary written by Colin Clark while he worked for Laurence – who directed, produced and starred in the film - as third assistant director. However, his unofficial role was to keep Marilyn out of Laurence’s way.
The diary has already been published but details of one specific week were left out. This missing time frame will become the basis of the story".
Scarlett Johansson 
and Amy Adams were also considered for the role".Source: www.imnotobsessed.com