There's one outfit that's become so classic and dependable in the wardrobes of millennial women, it's basically a cliché at this point.

We're talking, of course, about a blazer and jeans.

The combination works for most occasions, from casual to corporate, and it's a fail-safe option if you're facing a styling crisis.

Watch: How to apply the Wrong Shoe theory. Post continues below.

But have you ever thought about just what makes this combination feel so effortless?

In theory, teaming a tailored garment like a blazer with a fabric as overtly casual as denim shouldn't work on paper — but it does.

The reason? The dressy jacket is overcompensating for the jeans.

Rosie Huntington Whiteley demonstrates the effortless balance of an oversized blazer and jeans. Image: Instagram/@rosiehw.

Viral stylist and author Allison Bornstein says 'overcompensating' is often the key to styling tricky items.

The fashion expert laid out her theory in a video posted to her popular TikTok feed, suggesting that when you're pulling a look together, you should actually be styling against your instincts to create a more interesting outfit.

Stay with us here, because she's got a great example revolving around — you guessed it — denim.

@allisonbornstein6

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♬ original sound - Allison Bornstein

"Let's say you have a pair of ripped jeans. They're casual and they're slouchy, so your instinct might be to style it with something that's also casual and slouchy," the stylist explains.

In this case, she says you might defer to something like a leather jacket or band t-shirt.

But with this approach, you run the risk of looking costume-y, rather than cool and considered.

"You're playing into, and playing up, the qualities of these ripped jeans, so you're just kind of amplifying them," Bornstein argues.

Instead, she suggests you 'overcompensate' for the denim by adding a contrasting piece — like a pointed shoe to add sharpness, or a ladylike jacket to bring in a completely different silhouette.

The idea is similar to her viral 'wrong shoe' theory, which suggests styling a clashing shoe with your outfit instead of the obvious functional choice. Once again, it's all about the contrast.

In this outfit, personal stylist Fifi Milne contrasts her edgy white tank with an elevated leather skirt and dressy accessories. Image: Instagram/@shopwithfifi

"If something's going really far in one direction, like it's really edgy, instead of playing into that and styling the whole look around that concept, style against it," Bornstein adds.

"Think of what would be the opposite of that edginess."

Content creator and designer Nikki Parsons shows how to contrast a boho blouse with more casual, utility-style pieces. Image: Instagram/@stylingyou

Her theory might just explain the can't-put-your-finger-on-it appeal of some of the biggest trends to emerge this year.

Lace maxiskirts paired with oversized graphic tees. Sporty trackpants teamed with girlie cardigans. Coats worn with… thong heels.

If you think about it, one piece is always overcompensating for the other.

Stylist Emelia Morris teams a graphic tee with a lace maxiskirt. Image: Instagram/@emeliamorrisstylist

You can also apply this theory with accessories. If you're wearing a sporty look or loungewear, the relaxed fit can be upgraded with some sleek sunglasses and a chic suede handbag.

Or if you're in a printed maxidress, you can overcompensate for the boho vibes with a minimal sandal and sculptural jewellery.

Shop the story.

AERE Mila Relaxed Tailored Blazer, $160.

Image: Supplied.

Levi's Ribcage Wide-Leg Jeans, $159.95.

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Tony Bianco Imogen Black Python, now $150.

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MNG Oversized Cotton Jacket, $189.95.

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& Other Stories Classic Suede Tote, $199.

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Feature image: Instagram/@_tamaradavis_; Instagram/@shopwithfifi.