(Cover) - EN Showbiz - Michelle Williams immersed herself in the character of Marilyn Monroe so much for her latest film she feels her personality has been fundamentally changed.

The blonde-haired actress bears a striking resemblance to the classic Hollywood actress in My Week With Marilyn, which is told through the eyes of an employee of Lawrence Oliviers called Colin Clark.

The narrative documents the fraught relationship between Marilyn famed for her striking blonde locks and red lipstick glamour and Lawrence during the production of The Prince and the Showgirl in 1956, which took place in Pinewood Studios, England, where Michelles film has just finished shooting.

The 30-year-old actress confessed that working so hard to perfect Marilyns true character has had a significant impact on her.

At a certain point, something else does take over. I dont quite feel myself these days, she told British newspaper The Daily Mail. It rearranges you, it shifts your molecules, lifts you up, spins you around, puts you back down and youre not quite the same, for better or for worse.

The actress said it was a challenge to encompass the different aspects of Marilyns character, including her showbusiness public image, her true nature as Nora Jean the name her parents gave her- and also the multi-faceted character she plays in The Prince and The Showgirl called Elsie Marina.

At first the American actress turned down the part because she felt the differences between her and the legendary Hollywood star were too great.

But eventually Michelle agreed and was given tuition on how to perfectly carry off Marilyn on-screen.

I knew I wouldnt be able to resist, eventually, Michelle said. Physically and vocally, everything about her is different from me. Ive kind of gone to school and had teachers to help me understand Marilyn, so I could project an essence of her. (C) Cover Media