Shoppers were left stunned after learning the truth behind those tiny pockets on their jeans.

A quintessential component of wardrobes across the globe, jeans are famed for their versatility and come in an array of styles and hues. Yet, regardless of design, they all share a common feature - the mysterious little pocket which has baffled many.

The actual reason for this diminutive pouch stretches back to the 1800s, a time when it was fashioned as a convenient nook for stashing pocket watches.

A Reddit user's curiosity sparked a discussion as they queried: "In most jeans, there's an extra pocket in the right pocket - what is it for, and what do you use it for?".

These pint-sized pouches have their origins in the heyday of the 19th century, stitched into Levi's 'waist overall jeans' the original term for the now-iconic blue denim pants ideally sized for a pocket watch.

This innovative detail was patented by Mr. Strauss alongside J. W Davis in May 1873 under the title "Improvement in Fastening Pocket Openings", and first appeared in the mainstream market in 1890 with the Lot 501 jeans that became the blueprint for the iconic Levis 501s.

Levi Strauss & Co's historian Tacey Panek shared insights with Insider, revealing: "The oldest pair of waist overalls in the Levi Strauss and Co. Archives (from 1879) includes the watch pocket.