Most people who own a pair of denim jeans will have noticed that they come with tiny pockets.
However, have you ever wondered why they are there and what purpose they serve?
The answer can now be revealed - and it is a historical reason, The Daily Star reports.
The small pockets date back to the year 1890, when they were stitched into Levi's 'waist overall' jeans.
They were commonly used for carrying pocket watches back then.
Strauss and J.W. Davis patented 'Improvement in Fastening Pocket Openings,' on May 20, 1873.
Tacey Panek, Levi Strauss & Co's historian, told Insider : "The oldest pair of waist overalls in the Levi Strauss & Co. Archives (from 1879) includes the watch pocket.
"Our 19th century overalls had a single back pocket on right side of the pant beneath the leather patch."
The tiny pocket is apparently never found on suit trousers because a pocket watch would be part of the inside of a jacket for formal wear.
Seeing as not many people use pocket watches these days, it may seem a bit pointless they're still there.
However, it's actually due to sentiment with regards to WWII, as to why they are still in there.
Panek explained: "One interesting fact about the watch pocket is that during WWII the two corner rivets were removed as a way to conserve metal for the war effort."
"The rivets returned to the watch pocket after the war.
"It was riveted in the top two corners and included our recognisable arch design, called the Arcuate, stitched with a single needle sewing machine.
"The watch pocket was an original element of our blue jeans, like the rivets on our pockets, button fly, arched back pocket stitching and leather patch.
"To preserve the integrity of the early design, Levi Strauss & Co. maintains the watch pocket."
On the Levi's website, she wrote: "This cinch-free blue jean with the uniform look of the Arcuate, a contrast to previous years when the single-needle application made each Arcuate design unique, was the blue jean of the future and you can still see it in our 501 jeans more than 70 years later.
"Levi’s emerged from World War II as fresh, modern and uniformly manufactured.
"And with a distribution that now spanned oceans, it was well on its way to becoming the world’s ubiquitous global garment that it is today."
The news comes after it was also recently revealed why there are little pockets in women's underwear.
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