Poor Eddie Redmayne. Just because he looks quite like a girl, he finds himself a spokesperson for the burgeoning trans movement. Recently, he was forced to explain to those of us watching BBC News that ‘the notion of gender being binary’ is now considered ‘antiquated’.

People are very excited about being trans at the moment. Countless TV shows and films depict it, Mark Zuckerberg has just called his daughter Max, and a man called Hilary has just talked us into another war. Being trans is clearly catching: hermaphrodite whelks on the undersides of fishing boats are growing penises, and vast swaths of young people, unable to buy a home or get a job, now realise they are trapped in the wrong body. Well, great. Previously you only noticed trans people when you used a phone booth on the Tottenham Court Road — now they’re on the cover of Time magazine.

It’s appropriate that it took an actor to explain to everyone that gender identity is not binary but on a spectrum. Actors, who have no real sense of who they are or what they want, have long known that not just their gender but every aspect of their identity is on a spectrum. They can be anything they are asked to be. They aspire to a protean state, shape-shifting like high summer clouds.

In reality, they sell their bodies and emotional lives for money. They don’t need to use phone booths; they get their pictures in magazines. And they learn early that in order to make their way in the world, it’s best to leave questions of identity to others. If that’s what you think I am, then I’m happy to oblige. (Would you like me in the doublet and hose or the french maid’s outfit?) I like to consider myself a blank cheque on which people are free to ascribe whatever value they feel appropriate.

In some cases, given a degree of success, the previously noncommittal actor can get attached to the identity that has been ascribed to them, and this can lead to political activism. Eddie has made a seamless transition from actor who looks like a woman to being cast as the transgender Lili Elbe in The Danish Girl, to becoming spokes-woman on behalf of all trans people (may their tribe increase). Like Brigitte Bardot: adored sex bomb, to formerly adored sex bomb, to saviour of a formerly adored pets. Or most famously Ronald Reagan. Looks like a good guy, gets cast as an ordinary good guy, becomes President of the United States of Good Guys. Normally, there’s a few years of career-fade before the previously beautiful become politically active, but Eddie has magnificently leapfrogged that process.

I’ll have you know that as a young man I spent an entire year as a woman in a world tour of As You Like It. I played Celia. As a lesbian. I didn’t feel that much like a woman at first, but with makeup and a dress on I looked like one, and I was told it would be good for my career, so I had to get on with it. And it wasn’t a cheap drag act — no, no, we won awards. And that’s because we took it very seriously, and in our extensive rehearsal period we discussed at length what it be like to menstruate, how to fake orgasms, and the tricky business of getting out of a sports car in a miniskirt. And eventually, after a few weeks’ practice and some encouraging reviews, I was to all intents and purposes a woman — in my work life at least.

For years, I was similarly accommodating when it came to my sexuality. I didn’t feel particularly gay, but I was half-pretty and boyish, and a lot of gay people seemed to have very influential positions in the theatre. So I went along with it, up to a point. And I liked the attention. Any port in a storm, as they say. Quite soon this affected the parts I got. I graduated from restoration fops to actual gay people. To date, I have pretended to be about 11 different gay men and one gay woman, essentially for financial gain. Some of the men were really straight, but I played them gay, because eventually I couldn’t help it. I could probably have paid for half of a quite modest central London one-bedroom flat on the proceeds of my work as a homosexual impersonator. Well, good for me. It’s been marvellous.

I suppose if there’s a point to any of this, it’s that you can play around with notions of your identity, you can impersonate other people and it can be fun, but the moment you start to suggest that your actual identity is up for grabs — well that’s something else entirely. If it’s simply that the media exposure is allowing previously marginalised people to come out of the shadows and discuss something without shame, then that’s great. Bring it on. The fact that it’s fashionable doesn’t necessarily make it worthless.

But if it’s really true that new legions of people are genuinely saving up to have their genitals converted in the new year, then I suppose I must defer to a something that is clearly more profound, and actually beyond my understanding. The whelks previously mentioned were apparently affected by the anti-barnacle paint on the undersides of fishing boats. Perhaps, for the humans, it’s the plastic wrapping on cheese. Or the effect of the contraceptive pill in our water.

Who knows? Maybe Eddie does. I’m all for grey zones and liminality, and the truth at least is always in transition. We’ll see. In the meantime, make sure you have a non-binary, properly nuanced, happy-as-it-can-be Christmas.