Age: Christensen is 50.

Appearance: Black, lacy, sheer.

What are we talking about here? Christensen’s bustier.

Than whom? You misunderstand. A bustier is a form-fitting ladies’ garment, traditionally worn as underwear, that is designed to force the breasts upward. It’s pronounced “boost-yay”.

I bet it is. Who is Christensen, anyway? She’s a former Miss Universe Denmark who went on to become one of the original supermodels of the 90s. She has also worked as a fashion designer and a photographer.

And she has a bustier? She probably has a few, but she wore one to the model Gigi Hadid’s 24th birthday party last week.

Oh my God! Gigi Hadid is 24? Please concentrate on Christensen’s bustier.

I’m trying, but why would I care what some former supermodel was wearing under her top? She didn’t wear it under her top. She wore it instead of her top, attracting some pointed criticism.

I’m not surprised – she’ll catch her death. The criticism was about her mature years. “Why, at the age of 50, did she decide to pitch up ... in a tacky, black-lace bustier?” asked the former Vogue editor Alexandra Shulman in her Mail on Sunday column.

Why not? Shulman described the look as “madam in a one-horse town” and wrote: “Something you wore at 30 will never look the same on you 20 years later. Clothes don’t lie.”

Did Christensen have anything to say about that? Yes. She posted a picture of herself in a bustier on Instagram and wrote: “Let’s continue to elevate and support each other, all you beautiful, smart, fun, sexy, hard-working, talented, nurturing women out there.”

She took the high road. How cunning. Then there was a bit of a pile-on.

There was? Poor Christensen. The pile-on was behind her. Fellow supermodel Linda Evangelista said of Shulman: “She should be ashamed of herself.” Naomi Campbell described the comments as a “cheap shot”.

Ouch. Shulman’s successor at Vogue, Edward Enninful, called Christensen “BEAUTIFUL inside and out”, while another former editor said: “I think Helena is absolutely wonderful.”

Which former editor? Oh, that was Shulman backtracking, but she added: “I just didn’t think the corset was a good look.”

So the lesson is: you can dress as you please at any age, as long as you are incredibly good-looking in the first place. Exactly.

Do say: “If I looked like Christensen, I’d wear a bustier to the supermarket.”

Don’t say: “You must be freezing, love! Do you want to borrow a fleece?”