Critics have savaged "Diana", a biopic of the late princess of Wales who died in a Paris car crash 16 years ago, just hours after its world premiere.

Lead actress Naomi Watts has already defended her involvement in the controversial film, which follows Diana's romance with London-based Pakistani surgeon Hasnat Khan.

But within hours of the premiere, a string of merciless reviews in the British press shattered the party spirit.

The Times praised Watts for doing "her level best with a squirmingly embarrassing script" but concluded that the film was still "atrocious and intrusive".

"Poor Princess Diana," wrote Guardian critic Peter Bradshaw.

"I hesitate to use the term 'car crash cinema'. But the awful truth is that, 16 years after that terrible day in 1997, she has died another awful death."

The Daily Telegraph gave the film two stars -- one more than both the Guardian and Times -- but was also withering in its assessment.

"What's the point of 'Diana'?" reviewer Davis Gritten asked rhetorically.

Based on Kate Snell's 2001 book "Diana: Her Last Love", the film suggests that Diana started dating Dodi Fayed, whom many friends of the princess say was her real love, to make Khan jealous.

Source: Press Release