The temptation to play an extraordinary real life character must be overwhelming for an actor. Get it right and your cinematic interpretation will gift you personal satisfaction, critical acclaim and a mantelpiece creaking with awards.
However, get it wrong and prepare to reap the whirlwind of opprobrium. Naomi Watts is an exceptional actress who's been nominated for an Oscar on two occasions. She probably shouldn't expect a third for Diana.
The film about the late Princess of Wales has been mauled by critics, the kinder reviews calling it 'terribly, terribly dull' and 'fabulously awful'. More venal descriptions include 'atrocious and intrusive', 'mind-bogglingly misjudged', and even brutally, ‘car crash cinema’.
It's always a risk taking on the role of a beloved or well-known figure. Here then are five of the greatest cinematic successes when actors have played real people. But just for balance, we’ve also included five of our favourite failures.