The long awaited biopic 'Diana', in which Naomi Watts plays the doomed Princess, makes its world premiere in London on September 5th. But the controversial film about Di's private life almost wasn't made at all, at least with Watts in the starring role.

'I turned it down twice', said the 44 year old actress, who said her greatest concern was offending Diana's grown sons, Princes William and Harry.

The film details the late Princess's  love affair with heart surgeon Dr Hasnat Khan up until her death in August of 1997 from injuries sustained in a car crash in Paris.

The movie, which is based on the book 'Diana, Her Last Love', is, as of now, not set for release in the US.