I recently learnt that in the middle of summer, although it is still dark at 3am, the birds have already begun to sing.
With 10 years of a mortgage still to run, an early-retired headmaster must always be on the lookout for fresh financial opportunities and although supply teaching pays quite well, being a film extra did seem to have that added touch of glamour.
It started with a small ad in the evening paper that led to a photographic session in a village hall, followed by a payment of Pounds 25 to an agent and, ultimately, to two days' work on a television commercial for American Express.
One of the first things to learn is that people in the cinema industry work to a different clock from ordinary mortals. Keen not to arrive late, that was why on both days I was up at 3am.
This is the first indication that life as a film extra is far from glamorous.
"Extras" means just what it says, you are only there to provide background for the main action. Unless you are lucky you will not even be seen. There is also an awful amount of waiting around on a film set. It pays to take a good book.
For our first morning, although we were not due to start filming until 7.30, we had to be at our location in a recreation ground by 6am. There were 60 extras to kit out as part of an unruly football crowd and many also had to have their faces painted.
A section of grandstand had been set up and, by the time we had all been arranged to the satisfaction of the director, it was close to 8.30 when the American star of the piece was eventually fetched from his luxurious caravan.
By about 9.15, after 15 "takes", the director was satisfied and the 11 seconds of action were safely "in the can".
The following day we were rather more select. The location was a charming village in mid-Sussex where our hero was to visit a dog show. We were to provide what the script referred to as "snobs in fancy dresses, suits and hats".
Much of the day was spent in setting up and filming this 10-second shot and, as one looked at the lavish tented pavilion and marquee that had been set up simply to provide the hazy background, one could not help reflecting how much they would have enhanced the school summer fair. Yes, it is all part of a different world.
Despite the lack of glamour and the early starts, being a film extra can be great fun.
Mind you, it is just as well that this particular commercial is destined for American TV because I would be mortified if anyone were to recognise me as part of that football crowd.
Michael Evans is former head of Barton C of E primary school, Cambridgeshire