Frank Costello
The Character: Jack Nicholson's dildo-waving crime boss lies at the centre of the web of lies engulfing Damon and DiCaprio in The Departed .
The Inspiration: Costello's Boston roots and the twist that he is an FBI informant are a dead giveaway that he's modelled on real-life mobster Whitey Bulger.
Artistic Licence: Costello is killed, but Bulger - on the run at the time the film was made - was eventually arrested and tried, and now lives in prison.
Mick Taylor
The Character: Psychotic bushman and exterminator in the Australian Outback (played by John Jarratt in Wolf Creek ) who includes foreign backpackers in his definition of 'vermin.'
The Inspiration: Backpacker murders are a very real threat in the Outback, with cases such as Bradley John Murdoch's murder of Peter Falconio.
Artistic Licence: While Taylor is a composite of many killers, the film was deemed so close to the bone that its release was postponed in the Northern Territory so as not to prejudice the Murdoch trial.
Elliott and Beverly Mantle
The Character: Identical twins played by Jeremy Irons in Dead Ringers , whose close professional and personal ties get rather too entangled, bringing down both men.
The Inspiration: Cronenberg's film was loosely based on real-life twins Stewart and Cyril Marcus who, like the Mantles, were gynaecologists and drug addicts.
Artistic Licence: The Mantles die while under the grip of pills, with Beverly disembowelling Elliott and then himself dies of grief. Real life was more prosaic: the Marcus brothers died of barbiturate withdrawal.
Alice
The Character: Y'know, her what goes to Wonderland.
The Inspiration: Alice was named after Alice Liddell, a family friend of Charles Dodgson (aka Lewis Carroll) for whom the story was written.
Artistic Licence: Decades of literary scholarship have been spent trying to figure out the precise nature of the relationship between Dodgson and Liddell, but we're fairly safe in assuming that no invisible cats or mad hatters played a part.
Dirk Diggler
The Character: Mark Wahlberg plays the well-endowed Californian kid, nee Eddie Adams, who changes his name when he becomes a famous porn star in Boogie Nights .
The Inspiration: John Holmes, who similarly made his name on the size of his member.
Artistic Licence: Paul Thomas Anderson riffs freely on Holmes' arc (including his decline into cocaine abuse) but stops short of his AIDS-related death in 1988.
Officer Daniels
The Character: Alleged policeman voiced by Pat Healy in Compliance , whose false demands to interrogate a fast-food restaurant employee dupe several people into executing a terrible ordeal.
The Inspiration: Officer Scott, said to be family man David R Stewart, who instigated a string of hoax calls including the one that inspired Compliance .
Artistic Licence: Chillingly, this one is largely accurate. Even more disturbingly, the alleged culprit was never convicted.
Emily Rose
The Character: A young woman, played by Jennifer Carpenter, whose death sparks the events of The Exorcism Of Emily Rose .
The Inspiration: The film drew on the real-life case of German woman Anneliese Michel, who died in 1976 after being 'exorcised' with psychotropic drugs.
Artistic Licence: In real-life, the verdict was manslaughter, with Anneliese's death provoked by her epilepsy. In the film, there's enough Omen -style shenanigans to suggest Emily really was possessed.
Pete 'Maverick' Mitchell
The Character: Tom Cruise feels the need, the need for speed. Thankfully, there's plenty of it in Tony Scott's Top Gun .
The Inspiration: The film was inspired by a magazine article about real-life fighter pilot cadets. Maverick himself was loosely based on instructor Randall 'Duke' Cunningham.
Artistic Licence: After Top Gun , Cunningham became a Congressman, only to resign in disgrace after pleading guilty to bribery charges. There's your sequel right there, Cruise.
Maya
The Character: The CIA agent played by Jessica Chastain in Zero Dark Thirty , whose obsessive quest to track down Osama Bin Laden comes at the expense of… well, everything else in her life.
The Inspiration: Screenwriter Mark Boal has been cagey about declaring specific influences, but commentators have charted uncanny parallels between Maya and an operative known as 'Jen,' whose role in the Bin Laden hunt was featured in non-fiction book No Easy Day .
Artistic Licence: Given the film's need to focus on a single protagonist, it is unlikely that Jen would have been quite so omnipresent as Maya.
Dean Moriarty
The Character: On The Road 's charismatic rebel, "a youth tremendously excited with life" and a symbol of American counter-culture, who was played by Garrett Hedlund in Walter Salles' recent adaptation.
The Inspiration: Famously, Jack Kerouac based the character on his friend, writer Neal Cassady.
Artistic Licence: Moriarty and Cassady are as close as can be; in early drafts of On The Road , Kerouac is still using his friend's real name for the character.
