NEXT time you watch a film, pay a little bit more attention to the extras milling around in the background looking as though they are engaged in an intellectual, chin-scratching conversation complete with nods, hand gestures and the occasional chuckle.

These people, often actors busking for work, have probably given up their time for free and waited around for hours just to repeatedly walk over to the juke box and frown as though they’re pondering existentialism whilst a mere 15 seconds of a scene are filmed, and in that scene they will, very likely, be a shadow in the background.

I speak with a little bit of experience about being an extra, having joined the cast and crew as an extra for an all-day shoot of The Manual, which is currently being filmed at Oaklands’ Smallford Campus.

The Manual is described as a scientific-philosophical romance. The writer and director, Darren Paul Fisher, has likened it to (500) Days of Summer and Eternal Sunshine of the Spotless Mind.

The plot follows the lives of two young people who live in a society that is sorted into those that are lucky – high frequency people – and those that are unlucky – low frequency people.

In their world, a low frequency person dating a high frequency person is unthought of, until someone thinks of it.

It all sounds very intriguing and on the day that I join the set they are filming a science fair which requires students and tutors as extras.

I am told I’ll be a student and need to wear black trousers, black shoes and a white shirt – I wonder how that will work? I’m 28.

Perhaps I’m one of the unlucky students who keeps failing the year so they’ve been held her back. (Yes, really. I actually started creating a back-story for the student I would ‘become’. Her name would be Lucia – it seemed appropriate.)

It turns out though that I’ll play a tutor so Lucia is dumped and I quickly invent Ms Smith, a firm but fair teacher who is greatly respected by her students. She teaches art.

We stand in the main hall of the college where presentation boards are set up. Each board details scientific experiments the fictional students are presenting to their classmates and their tutors.

It all looks quite perplexing to me but then it occurs to me that Ms Smith is an art teacher and probably hated science at school so I now have my ‘motivation’ for the coming scene.

The other extras all arrive and we are told to take off our shoes to avoid making extra noise.

The extras are a range of performing art students at the college and some from local stage schools. They are all a wonderful credit to themselves and, having spent all of the previous day in the same positions, take to their roles like professionals.

The principal actors arrive and we roll: the director and camera man get into position and we have our first ‘action’.

For a moment I forget to move. George, who is playing a student and standing beside me, stirs into action and starts miming how his scientific project works. I nod encouragingly and move on to the next student’s stand.

I get another silent explanation and begin to feel more confident so I mime a question to the other extra and off we go: we’re acting! I thought we might mouth ‘rhubarb’ at each other – that’s what my drama teacher had once told me extras did – but we don’t. I try it and look like I’m blowing kisses at people.

The scene happens quite a few times. Quite a few… but in between each take I am really taken with how upbeat and enthusiastic everyone is.

Everyone here is giving up their weekend for free and nobody gets exasperated, however many takes there are.

After a short break we are given new instructions. Whilst two principal actors talk we will walk past behind them to create the bustling atmosphere of the fair.

The director calls action and we all surge past the ‘hot spot’ – the place where we’ll definitely be in the background – as though we’re being marched at gunpoint. The director laughs at us and asks us to stagger our walk-by moments.

In order to do this effectively, we are asked to do a circuit around the room and be aware that as we pass the ‘hot spots’, we’re on camera.

We do many, many laps of the room in silence apart from the actors’ lines. We are like zombies until we reach the hot spot when backs straighten, heads start to nod and mouths begin to mime. Once we’re out of the zone, we slouch around the room waiting for our brief moment to shine.

It’s a lot of fun and I get to chat with lots of interesting people who all have a passion for films and performance. For many young people at the college, the experience has opened their eyes to what film acting can actually mean: a lot of waiting around and repetition.

It’s also shown them the amount of work there is on the other side of the camera.

It is a less than glamorous process and it requires a lot of stamina. Because so many young people are involved they finish in the late afternoon but it’s quite normal for adults to work 16-18 hour days when on a film set.

And they’re certainly important enough to require a bit of recognition in your future movie-watching: imagine Ben-Hur without the 8,000 extras or Ghandi without its, wait for it, 300,000 extras in the final funeral sequence. That ‘background action’, as it’s termed, is part of what makes a movie seem so real.

The Manual won’t hit cinemas for quite some time yet, but when it does, pay close attention at the science fair for Ms Smith as she hurriedly checks her invisible watch and scratches that very itchy nose because that’s me, smelling my Oscar.