There are a lot of things that black movie stars don’t usually tell you. Like how, as one major LA agent told me, even the most famous have struggled for years to enjoy anything like the same level of income from brand endorsements as their white peers. A black Hollywood A-lister told me she got through an entire major big-budget movie with a £30 wig from a downmarket hair shop because on day one of filming, it was all she had on her; no one had thought to source anything better. And no one talks about the devastation of hair loss, and the damage and vanishing hairlines that come from years of bad styling on set.

David Harewood – the black British actor who has made it big in the US on series such as Homeland and Supergirl – told me about his history of botched barbering attempts when I interviewed him for my book Brit(ish). “Every time I work in the States, I have had to have my hair cut outside of the set,” he said. “And I think to myself: ‘Surely this is wrong – why am I having to go and drive half an hour up to the road to a black barber?’ It’s not just principle, but a business case – think of the time I’m losing!”

Now a number of American actors are speaking out, describing how they have to invest their time and money on hairstyling that white actors consider part of the standard pre-production process. “Most black actors get their hair cut or styled outside of set, often at their own expense, because Hollywood hairstylists are one-size-fits-all and that ‘all’ does not include black hair,” tweeted Malcolm Barrett from the drama series Timeless.

The British star Susan Wokoma, beloved for her appearances in the Netflix series Crazyhead and Channel 4’s Chewing Gum, described the anxiety she still feels about having to work out, alone, how to manage her hair in advance of a new job: “The amount of times I’ve seen white co-stars get their hair cut and coloured and other intricate things on a truck – yet I have to spend my weekend or day off traipsing around looking to get my own hair done …”

These actors are describing something that has affected me for years, and the only reason I am surprised is because I assumed movie stars – with their trailers, stylists, wardrobe budgets and personal hair and makeup teams – are of a completely different order to the unglamorous world of current-affairs TV that I usually inhabit. This world involves endless arguments over Brexit, tolerating ignorant and sometimes racist commentators live on air and discussing breaking news lines with no time to prepare. I have to say I’ve always found that relatively undaunting compared with the stress of having to devise and implement my own on-air hair strategy. White colleagues have this done for them. But having experienced the look of terror that fills the eyes of a makeup artist as I enter the room, followed by the inevitable, “You don’t want anything done with your hair, do you?” in an unmistakably pleading tone, I assumed it would be unreasonable to ever answer, “Yes, please!”

Instead, black women on TV employ a range of different tactics. Someone I have worked with pays for her own hair and makeup artist to accompany her everywhere she goes, after years of learning the hard way not to rely on broadcasters to step up to the mark and provide someone competent.

I often wear wigs so that, in the event of catastrophic styling, my real hair will survive intact. This was advice I was given by one of the very few black makeup artists I have ever encountered in a TV studio, who warned me to invest my own time and effort in having wigs made for me so that I could ensure continuity in case of: 1) filming in bad weather (everyone knows water is like kryptonite for afro hair); and 2) clueless hairdressing. I was grateful for this advice – it gave me a coping mechanism for dealing with this reluctance to touch our hair, a reluctance many of us internalised into the idea that being black was a specialist situation.

I can already hear the backlash coming – the allegation that this is the moaning of privileged people who don’t know how lucky we are. But understand this: TV and film are visual media, into which production companies invest significant money on hair and makeup for both men and women. White actors or contributors are treated to the planning, support and resources to get this right. Our appearance as black contributors, on the other hand, is an afterthought, or not thought of at all. And if black superstars can’t expect equal treatment to their white peers, what does that say for the rest of us?

• Afua Hirsch is a Guardian columnist