Reese Witherspoon, 42.

Kate Beckinsale, 45.

Tyra Banks, 45, who stretched it to 18 years.

Madonna, 60.

Jennifer Lopez, 49 (who included a pregnancy pic).

Elizabeth Banks, 44.

There were dozens of stars who took part and none of them appeared to have aged a day. In some cases, they looked somehow younger than they did ten years ago. Are they, as so many commenters have enthusiastically suggested, actually ageing backwards? What, in the name of unrelenting beauty standards, is going on?

“It goes without saying that all of these celebs are already naturally pretty and have good genetics,” says cosmetic physician Dr Phoebe Jones. “Most seem to practise quite healthy lifestyles, too.”

Loading

And yet, according to Dr Jones, it’s all of these things combined with cosmetic treatments that explain why these people look as if they’re auditioning for a Benjamin Button sequel.

For example, the only way we can tell that Jennifer Lopez has produced a photo from 2008 is because she told us so in the caption, (well, that and Google).

“J.Lo. is amazing,” says Dr Jones. But?

“I think she has a talented cosmetic doctor who has her on a good skincare regimen, as well as micro anti-wrinkle injections and skin boosters.”

Witherspoon, too, has, according to Jones, had some minor work done. Jones believes she’s used fillers, such as Restylane, around her mouth and cheeks. “She hasn’t altered her appearance too much, other than using conservative amounts of [dermal fillers] to replace the volume lost with ageing.”

Loading

But, how does viewing these images, alongside our own, less inspiring attempts at the challenge, affect us?

“These sorts of images of celebrities highlight the unrealistic standards set for beauty, especially for women,” says University of Canberra associate professor and clinical psychologist Vivienne Lewis, who specialises in body image.

“It is unfair to compare a non-celebrity woman’s body to one of celebrities. We don’t have access or the money to afford the cosmetic surgery that celebrities have.”

This point – that celebrities weren’t showing off their age-defying powers, so much as their privilege – was made by actor and comedian Billy Eichner, who posted the following announcement to his Instagram.

“I’m not doing the 10 year challenge.”

One fan voiced their support in the comments. “Good," they wrote. "Tired of celebrities doing the 10 year challenge when they look the same or better because let’s be honest, money…”

Eichner responded, “As someone who was completely broke and in debt 10 years ago and now has money, I can tell you this is completely 100% TRUE.”

And this is the lie at the core of the “challenge” undertaken by famous women on social media – it can’t be called a “challenge” if there’s nothing to be overcome. The idea would be farcical if it weren’t so pervasive.

We only have to look at last week’s Golden Globes to see the indomitable Glenn Close, 71, accepting her award and making a broadly feminist speech about women allowing themselves to soar – while she dabbed at tears on her smooth, almost completely line-free face.

The message seems to be: women are rising up to be strong, fearless, and vibrant – we are here for the long haul! But you’ll never see us age.

The result can only mean greater self-hatred, something Lewis has seen too much of.

“We need to love our bodies because they are real bodies” says Lewis.

“Your body should be treated like your best friend, with respect and dignity.”

But how can women practice having respect for a body in the face of the dominant culture, which keeps telling them they can now do anything they want – just so long as they’re young and pretty?