Dear celebrities: The Met Gala is a costume party, not a Year 12 formal.

In theory at least, the Met Gala – a fundraising benefit for the Metropolitan Museum of Art in New York City – is a chance for the world’s A-list to err on the side of eccentricity in gracing the red carpet.

The event is formally known as the “Costume Institute Gala”, and that’s exactly what it should be: a costume party. Both the setting and the annual ‘theme’ lend themselves to creativity and absurdity and celebration in fashion design.

Except for this year. This year felt more like a year 12 formal.

It’s far from understandable. The theme for this year’s event – held Monday night in the US – was Rei Kawakubo/Comme des Garçons: Art of the In-Between.

Kawakuba is a designer who reacts to a standing ovation not with elation, but with worry. “If everybody thought it was beautiful, it would be time for Rei to stop,” the designer’s husband Adrian Joffe told The New York Times.

Her past work has seen ballet tutus paired with leather biker jackets, while her 1997 spring collection “Body Meets Dress” was described by critics as a range resembling “tumors and abnormalities”.

The tagline of her brand Comme Des Garçons is “Wear Your Freedom”.

Here’s a taste of what’s possible at an event honouring Rei Kawakubo:

@KatyPerry in COMME des GARÇONS for @VogueMagazine May Issue, in honor of the upcoming @MetMuseum exhibition. Styled by @therealgracecoddington, and photographed by @mertalas and @macpiggott #MetKawakubo #CostumeInstitute #MetGala hair by @juliendys

A post shared by Comme des Garcons OFFICIAL (@commedesgarcons) on Apr 13, 2017 at 11:41am PDT

A post shared by Comme des Garcons OFFICIAL (@commedesgarcons) on Mar 5, 2016 at 12:24pm PST

As for today’s Met Gala lineup? Well… ummm… this is awkward.

Perhaps the US postal service has been having problems (another casualty of the new administration, no doubt) but we’re starting to question if the great majority of guests at Monday night’s event actually received the invitation.

(It’s feasible: I hear guided tours at the Metropolitan are worth turning up for, even on days that aren’t the Met Gala. It could be pure coincidence.)

So many guests failed to turn up in costume. And we don’t know why. 

The Kardashians look like they could be going to a cocktail party. Or maybe a frat party. There are surely red plastic cups on the bathroom vanity.

annual bathroom selfie

A post shared by Kylie (@kyliejenner) on May 1, 2017 at 7:55pm PDT

Gwyneth Paltrow could be a “doesn’t-want-a-fuss” bride tying the knot in a private ceremony in the Greek Islands. Only family is invited, the ceremony begins at 3pm.

What is asap thinking to himself? #MetGala #asaprocky #captionthis #gwenythpaltrow

A post shared by Own No Loops Podcast (@ownnoloops_podcast) on May 1, 2017 at 8:56pm PDT

Selena Gomez is definitely brunching. She’ll have the avo toast. Maybe a decaf — easy on the sugar.

@metmuseum 2017 Red Carpet | Get the Look: Dress Like Your Favorite Celebrity @selenagomez for Your Wedding ???????? . . . #selena #Photo by Rex/ @shutterstock #selenagomez #MetGala #metgala2017 #Vogue @voguemagazine #VogueMagazine #Metball #redcarpet #RedCarpetQueen #selqueen #metropolitan #metropolitanmuseumofart @yolancris @moniquelhuillierbride #YolanCris #MoniqueLhuillier #YolanCrisBride #MoniqueLhuillierBride

A post shared by Central Weddings (@centralweddings) on May 2, 2017 at 2:29am PDT

The only dress that did make headlines for its absurdity was that of Kendall Jenner. And it wasn’t really a dress at all.

Kendall Jenner, dont la “tenue” a suscité beaucoup de réactions, hier au #MetGala. ???????? #kendalljenner #kenny #newyork #gala #metgala2017 #only #louboutin

A post shared by Gossip Room (@gossiproomoff) on May 2, 2017 at 12:33am PDT

It’s simple really: Those who haven’t dressed up shouldn’t be allowed in.

There are no excuses (dodgy postal service aside) because it’s a lesson in manners we learnt in our childhoods.

We learnt it in Year Two when Annie was having a princess themed birthday party and we thought we were too cool to wear a costume and were subsequently grounded for calling all princesses “stupid”.

We learnt it in high school when we weren’t allowed to attend the athletics carnival if we weren’t dressed in our team colours. Detention always followed.

Listen: At least there weren’t any wardrobe malfunctions on today’s red carpet. (Post continues.)

We learnt it again at university when we discovered the easiest way to ensure free entry into a sold-out toga party was to be the best Cleopatra on campus.

In the words of my mother: “You are never too cool to wear a costume. No one cares if you think princesses are stupid. And, if you’re not dressed to theme, you won’t be allowed in”.

Come on Hollywood, you can do better.

Who was your stand-out from the Met Gala?