I wasn't always so accepting of my 50 shades of grey. Before filming The Pianist in 2002, director Roman Polanski, who was notoriously anti-wig, posted me to Paris to have the pigment removed from my hair. It was a Sunday and neither Jean Luc nor I wanted to be there. It took seven hours and turned my brown human curls into pewter-green horsehair. I wept on the Eurostar and insisted on wearing a grey wig in the film.

Though initially Polanski could barely speak to me, one morning he strolled on to the set and purred, "That wig is fantastic. I don't know why you didn't want it in the first place."

But embracing the grey has meant more recognition. I don't mean, sadly, in career terms. I mean public recognition in John Lewis and M&S, and while picking up Basenji droppings in Hyde Park. "If you're who I think you are, I wanna thank you for all the pleasure," said a burly, bald geezer in shorts. "You're looking great!' he added, kissing my hand and chops in succession. "And always remember" he yelled as he ran back to his white van, "a dog is always more reliable than a man."

Sometimes, hair can be so revealing. Casting my eye around the Wigmore Hall, I noticed two Grenfellian women, perhaps a decade my senior. One had hairgrips propping up a 60-year-old style choice and the other had carefully combed and sprayed the front and sides of her charcoal bob, while leaving the fuzzy back  in a perfect  representation of last night's sleep pattern. It moved me almost to tears.

Meanwhile, hair is a pain in the bun from cradle to grave; source of malcontent between mother and daughter; feminine allure that must be covered by Muslim and Orthodox Jew alike; explanation for tantrums in follically-challenged footballers.

But what is it actually for? Over to you, Mr Chambers: "Hairs regulate the body temperature by reducing heat loss from the skin and trapping warm air next to the body." There. And you thought it was just the subject of a 1960s love-rock musical.