The shoulder button on your jacket has a surprising purpose. [Photo: Twitter]

If you’ve ever owned a military-style or leather jacket, it’s likely you will have wondered about the button and strap combination on the shoulders.

And it turns out this feature isn’t just decorative – it actually holds the fairly handy purpose of holding your bag strap up, as the below tweet demonstrates.

Francheska Horsburgh, 18, from Cumbria is responsible for the revelation which had fellow Twitter users sharing her ‘Ah ha’ moment.

She tweeted of her surprise after realising what the button on her jacket was for – “Who knew?”.

Taken me 18 years to find out that the weird shoulder buttons on jackets is to hold your bag in place so it doesn’t fall off🤯who knew pic.twitter.com/IMLqAb0K3s — Francheskahorsburgh (@Francheskahor6) October 29, 2018

The post has since gone viral, receiving 56,990 retweets and 141,784 likes at last count.

While we’ll be making good use of our jacket shoulder buttons in future (no more slipping bag straps – hurrah!), the origins of this design feature is actually more complicated.

Shoulder buttons and the piece of flat material they come with are also known as shoulder straps or epaulettes.

In traditional army uniforms, epaulettes are used to attach ornamental shoulder pieces or decorations (which are also, confusingly, known as epaulettes) to jackets. This marks out whether a soldier is in an elite rank.

Shoulder buttons aren’t the only confusing feature on our everyday clothes. We also discovered what that tiny pocket in our jeans is for – spoiler alert, it’s not just for snacks.

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