Naomi Watts was worried about how Prince William and Harry would feel about the 'Diana' biopic.

The 44-year-old actress - who stars as the late Princess Of Wales in the forthcoming film - was concerned that Diana's children may not approve of the forthcoming picture which is based on the people's princess' romantic life with heart surgeon Hasnat Khan.

Naomi told InStyle magazine: ''That was another reason I was really holding back because you always wonder how they [her boys] feel about it. That's always the big thing in my mind, you know, would they approve?

''I know for certain there's nothing offensive in this movie. It's really the retelling of her life. The boys are in it for one scene. Their presence is there but it is the focusing on that love story.''

The blonde beauty wanted to ensure Diana's character was true to life and became fixated on the princess' interview with Martin Bashir which was originally broadcast in 1995, to the point where she was watching it even while working out.

She previously said: ''I ran the Martin Bashir TV interview so often that it got to the point where I was watching it on my iPhone while I was out jogging.

''I had five minutes of her walk, five minutes of her wave, five minutes of her laugh that I'd watch again and again.''