Sometimes acting on a movie gets way too real. Simulations can become real-life sitations - which can be both entertaining for the viewer and traumatic for the stars. Or just a big source of amusement for everyone involved. Winona Ryder recently confessed that she might genuinly be married to her 'Dracula' co-star Keanu Reeves.

Bram Stoker's DraculaBram Stoker's Dracula

The pair wed as Mina Murray and Jonathan Harker in the 1992 Francis Ford Coppola movie 'Bram Stoker's Dracula', but Winona reckons there nuptials were valid because a real Romanian priest oversaw it at a Greek Orthodox church.

'We actually got married in Dracula. No, I swear to God I think we're married in real life', she told Entertainment Weekly. 'In that scene, Francis [Ford Coppola] used a real Romanian priest. We shot the master and he did the whole thing. So I think we're married.' 

Even Francis can't deny that there might be something geuine about their vows. 'When we were all done, we realised that Keanu and Winona really are married as a result of this scene and this ceremony', he said. 

Real Sex

Real marriage might be a rarity in movies, but unsurprisingly, real sex isn't. We're not talking about porn either; unsimulated sex has been a feature in multiple Hollywood classics including Tinto Brass' 'Caligula', Vincent Gallo's 'The Brown Bunny', William Friedkin's 'Cruising', John Waters' 'Pink Flamingos' and pretty much any Lars Von Trier movie you can think of.

Sometimes the sex is performed by porn actors; Lars prefers to superimpose real genitals onto the main stars of his film, for example, but other times the actors have been willing to go that extra mile. Mark Rylance and Kerry Fox took their 2001 British indie film 'Intimacy' very literally, and Robert Pattinson has admitted doing whatever it took to get the perfect O-face in 'Little Ashes'. 

Little AshesLittle Ashes

'I played Salvador Dali and had to do a lot of scenes where I was naked, and I also had to masturbate. I mean really', Pattinson confessed in 2013, admitting that faking his expression 'just doesn't work'.

More disturbingly, it's well-known that Bernado Bertolucci encouraged Marlon Brando to sexually assault Maria Schneider in 'Last Tango In Paris' to produce a genuine reaction from her. She had not seen the scene in the script, and later confessed to feeling violated by both men.

Real Reactions

Real reactions aren't such a rare thing in cinema either. They could be something as simple as Will Smith's famous line in 'Independence Day' ('What is that smell?!'), or as dramatic as Shelley Duvall's emotional breakdown in 'The Shining'. The latter might have seemed relevent to the story, but her tears and exhaustion were actually the result of systematic emotional abuse by Stanley Kubrick.

Unfortunately, this kind of emotional torture happens to kids on set too. Drew Barrymore's hysterical reaction to the E.T. was absolutely genuine as she had not seen the puppet prior to the shoot. Gene Wilder also had a habit of scaring the kids on 'Willy Wonka and the Chocolate Factory' and Macaulay Culkin still has a scar on his finger from when Joe Pesci bit him in 'Home Alone'.

Home AloneHome Alone

'I got really mad at him', Culkin recalled. 'I was like, 'I don't care how many Oscars you have, or whatever - don't go biting a nine-year-old! What the heck's wrong with you?''

Real pain happens all the time on screen with actors managing to avoid breaking character too much. Like when Edward Norton punched Brad Pitt in the ear in 'Fight Club'; it was later revealed Pitt was expecting a gentle punch in the shoulder, but David Fincher changed the directions without him knowing.

Perhaps the funniest on-screen pain moment was when Steve Carell decided to allow his hairy chest to be waxed for real in '40-Year-Old Virgin'. He really didn't think it would hurt that much, apparently.

Real Injuries

Of course, with real pain comes real injuries. Jake Gyllenhaal cut a pretty gnarly gash on his hand when he punched a mirror in 'Nightcrawler', and Leonardo DiCaprio acted so hard in 'Django Unchained' that he smashed a glass and cut his own hand while filming - but didn't even flinch. He carried on acting and got stitches later.

The same can't be said for Viggo Mortensen in 'Lord of the Rings: The Two Towers'. He'd filmed a scene several times that involved kicking a helmet across the grass, but the take used in the movie was the final one where he broke a couple of toes and screamed in agony. 

The CrowThe Crow

Rarer, though, is when a genuine fatality is recorded in cinema history. The most notable is Brandon Lee's death in 'The Crow', where he was shot and killed after being hit with a defective blank. It happened eight days before filming was due to wrap, and there have been plenty of critics over the producers' decision to leave his death in the film.

More: Jake Gyllenhaal's method acting in 'Nightcrawler'

Sometimes though, the acting is so good it rouses suspicion. Ruggero Deodato directed a film called 'Cannibal Holocaust' which was so grisly, he was initially charged with making a snuff film. He was later cleared when it was proven that no-one died on set. Not that we would have been surprised.