When you’re watching two stars getting it on in a film, you might not always be sure if they’re really getting it on or if it’s a bit of movie magic.

Often, sex scenes use a bit of camera trickery and acting skills to make it look real. Or perhaps the actors opt to have a body double used so they don’t have to be involved in the X-rated bits.

Sometimes though, stars do go the whole hog and have unsimulated sex on screen, with a number of British stars having done so.

And if that’s a bit of film trivia you’re into, then there’s an entire list of films where actors have actual unsimulated sex in them shared on Letterboxd.

The Nymphomaniac films were of course on the list too. (Nordisk Film)

Of course there are some usual culprits that make the list such as the infamous Caligula which had to have so much footage cut out before it was evenr allowed to be shown.

The flick was immediately banned in a number of countries, with Italy seizing film reels of it that entered the country and branding it ‘flagrantly obscene’.

It starred big names of cinema such as Malcolm McDowell, Helen Mirren and Peter O’Toole and eventually a new version was released that was better received by critics than the original.

The list also features the likes of Antichrist, I Am Curious (Yellow) and Starlet.

It’s got to be said that some of the films included do seem to be adult movies from time gone by, there are some more recent titles like 2008’s Little Ashes with Robert Pattinson. There’s also Dogtooth, It is Fine! Everything is Fine and Stranger by the Lake.

Things have changed since some of the older flicks on the list though (like 1964’s Blow Job, 1973’s Female Vampire and 1972’s Pink Flaming).

The role of intimacy coordinators has only grown in film production, with stars speaking their praise.

Robert Pattinson in Little Ashes. (Regent Releasing)

Nicole Kidman recently spoke out about her part in the film Babygirl, which had ‘radically long takes’ during the (not real) sex scenes.

Intimacy coordinators worked to ‘precisely structure a given sequence’s many twists and turns’, and Kidman said she ‘never came out of it, really’ during filming.

She said while the lengthy filming process often left her feeling ‘ragged’, she still felt ‘incredibly safe’ thanks to the effort that went into the scenes.

Perhaps with such precise coordination and work going into sex scenes there’s not really a need for them to be unsimulated any longer.

If the alternative, which most film shoots like Babygirl use, is enough to look like the real thing then perhaps the movie with unsimulated sex in it is a dying breed. But in some cases, it’s down to the choice of the actor.

There are other dangers to doing it unsimulated as well, as actor Melvin Van Peebles wrote, produced, directed and appeared in Sweet Sweetback’s Baadasssss Song where he contracted gonorrhoea from a co-star.