Naomi Watts believes she and the makers of new biopic 'Diana' have treated the late princess' life ''sensitively''.

The 44-year-old twice turned down the role of Princess Diana - who tragically died in a Paris car crash in August 1997 at the age of 36 - before eventually taking on the challenge of telling the tale of the last two years of her life.

Naomi accepts the film is controversial but she is adamant it has been made with the utmost respect for Diana - who separated from Prince Charles in 1992 with their divorce finalized in 1996 - and her sons Prince William and Prince Harry.

Speaking at the movie's world premiere at the Odeon cinema in London's Leicester Square last night (05.09.13), Naomi told BANG Showbiz: ''I expected nothing less than it to be controversial, it's a sensitive subject. Diana was and is so loved ... I always expected criticism and uncomfortable questions. I just hope we've told the story in a sensitive and respectful way.''

Naomi admits she struggled to master the mannerisms and voice of Diana and ensured she worked hard to mimicking the iconic lady's most famous look.

She said: ''The voice and the dialect were tough. She moved her face in very different ways. Trying to master 'that' look from underneath the fringe, which was such a memorable one, was hard. I had to get that right - obviously.''

Naomi was joined on the red carpet by her co-star Naveen Andrews - who plays Diana's lover Dr. Hasnat Khan - Douglas Hodge, who portrays Diana's butler Paul Burrell and director Oliver Hirschbiegel.