Naomi Watts wanted to play Princess Diana because she was such a "complex" woman. The 44-year-old actress portrays the late royal in new movie 'Diana' - which is based on the book 'Diana: Her Last Love' and focuses on the last two years of her life including her romance with Dr. Hasnat Khan. Naomi initially turned down the part twice but was compelled to take on the role because she found Diana - the mother of British Princes William and Harry - so fascinating. Speaking at the world premiere of the film in London she said: "Any woman I take on (on screen) I want them to be all things. I'm fascinated by women who are complex, full of contradictions, who are fun, intelligent but fragile at the same time. "Someone who is going through something, some kind of transformation and this story is definitely that." The Hollywood star was determined to bring that side of the princess to the movie. She added to BANG Showbiz: "It seemed to me, in the research that I did, that Diana had a great spirit and a great sense of humour and a mischievous way and I definitely wanted to incorporate that in my portrayal."