Trust me, I have never been ready for my close-up. But when I backed the new silent film project London Symphony, I recklessly ticked the box to say that yes, I’d be in the movie. I envisaged the back of my head in a crowd, perhaps. Something nice and anonymous.

But cometh the hour, cometh the poseur, and today I spent an hour or so shooting a snippet of a scene for London Symphony. Or sitting mostly still and doing what I was told while trying not to get the giggles. Here’s what I learned from my experiences on a silent movie “set”:

• There’s a reason those silent-era directors had megaphones. We were filming on the Victoria line (yes, we had permission) and while no doubt director Alex Barrett was talking me through my big scene, I could barely hear a word he said.
• There are a lot of angles to cover – two cameras, shooting front-on, overhead, from a distance, crammed next to my cheek … The London Symphony crew were using handheld digital cameras, of course, I can’t imagine how this would play out with a wooden-boxed hand-cranked job.
• I didn’t realise how much structure dialogue gives to a scene. I’m not an actor, so of course I was going to feel a little self-conscious being photographed by those moving picture contraptions. But without anything to say, I really felt a little untethered. Anything could happen! Luckily Adam Hickey, the actor I was working with, was actually an actor and very professional.
• Londoners are not in the least bit fazed by seeing people filming and playacting on the tube. We caused not a ruffle. Though Alex did tell me that amateur photographers often approach him in the street to chat about the gear. Mmmm, lenses.

• The only acting advice I could remember was given to me by an aunt of one of my friends when I was a teenager. She had been a Tiller Girl back in the day and she said “Only half of it shows.” I applied this rule, but mostly to my eyeshadow.
• Aspect ratios are tricky. The London Symphony film are shooting on 16:9 cameras, but the film will be 4:3. The solution: strips of white card taped to the viewfinder. Surely Canon will introduce an “Academy setting” soon.
• The film will also be black-and-white – trying to imagine the world around you as monochrome was fun, but quite disconcerting.
• Everything changes, especially the script. Even the little “bit” that we played out today turned out very differently than it was originally planned. Alex tells me that the film is constantly evolving – the style is becoming more modern, less like a copy of silent-era city symphonies and a little more 2015. Also, they are shooting lots (and lots) of footage all across the city, so they can develop new ideas on the fly, and in the edit.

Let’s hope my face doesn’t hit the cutting-room floor, then you will be able to see what I mean when the film gets released, probably next year.

• Find out more about London Symphony at Londonfilmsymph.com