Naomi Watts says she really believes Princess Diana gave her “permission” from beyond the grave to play her in a new film about her love life.

Naomi Watts, 44, admits the claim will sound unusual, but says the experience left her feeling more comfortable in the title role of the movie Diana.

Playing the Princess was, says he British-Australian actress, her hardest ever role.

“I kept wondering to myself <<Would she like it?>>,” Naomi Watts reveals.

“So I found myself constantly asking for her permission to carry on.  I had saturated myself with Diana and her life and I felt this enormous responsibility of playing this iconic woman.

“It felt like I was spending a lot of time with her. There was one particular moment when I felt her permission was granted. That won’t sound right in print, I know.”

Naomi Watts, whose previous film roles have included The Impossible and Mulholland Drive, feared that she was not physically similar enough to Princess Diana, who died in 1997.

The biopic, which opens next month, focuses on the final two years of Princess Diana’s life and includes details of her relationships following her divorce from Prince Charles – notably with Dodi Fayed and with heart surgeon Dr. Hasnat Khan.

Naomi Watts says she really believes Princess Diana gave her “permission” from beyond the grave to play her in a new film about her love life

Dr. Hasnat Khan, played by Lost actor Naveen Andrews, met Princess Diana in 1995 and their relationship is understood to have grown very intense – even talking of marriage together and starting a new life in Australia.

Producer Robert Bernstein has explained how the film-makers approached the relationship sensitively after discussions with Dr. Hasnat Khan and his family.

He said: “The way we are treating the relationship is one of a romantic and tender nature, in keeping with how we feel about Diana  and her life.

“It’s a very aspirational, sympathetic portrait and not voyeuristic. Our sense of their relationship was that it was very spiritual and sensitive, as well as difficult, obviously. We are handling it very sensitively.”

Princess Diana’s secret affair with heart surgeon Hasnat Khan ended when they both realized that they couldn’t live a “normal” life, says the film’s screenwriter, Stephen Jeffreys.

“I think Diana was very attracted to Hasnat because of what he did. He had wonderful surgeon’s hands and eyes and she was tremendously excited to be near someone who was doing good work.

“However, in order to do that good work he couldn’t possibly be in the eye of a media storm.

“When you are doing 12-hour-long heart operations you can’t come out of that and then have a her towards him meant they couldn’t stay together.

“I think that it was a relationship, which I’m sure we’ve all experienced, where you go on longer with it than rationally you should.

“You kind of know it’s not going to work and there are clear reasons why, but the heart overrules the head.”

Stephen Jeffreys, who based his script on journalist Kate Snell’s book, Diana: Her Last Love, and his own extensive research, believes there was a chance that, had she lived, Diana and Khan would have got back together.

“There was an escape plan that they would go to South Africa or Australia when the boys were older. But in the end I think it was a love affair that was defeated by practicalities.”

Stephen Jeffreys’ screenplay centres on the relationship between Khan and Diana. Her more publicized romance with Dodi Fayed, who died in the same Paris car crash that killed her on August 31, 1997, only features briefly at the end of the film.

“Our view is, that relationship is less important – it was a summer romance; having looked at what she said, you feel that it was a bit of fun for her.”