New coins portraying King Charles III are being released into circulation - but have you noticed this unusual detail?

One Wiltshire business certainly has.

Collector specialists at the Britannia Coin Company, based in Royal Wootton Bassett, spotted a surprising symbol in the portrait of His Majesty which has been used to create the likeness of our new sovereign's side-profile on pieces of pocket change.

Here's a hint - look at the King's ear. Don't worry, I didn't spot it at first, either.

Swindon Advertiser: The coins featuring King Charles and (right) the portrait used as referenceThe coins featuring King Charles and (right) the portrait used as reference (Image: Britannia Coin Company)

Eagle-eyed viewers will notice that King Charles III has what appears to be a bird of some sort in front of his ear.

This may commemorate his love for nature and the environment - but pictures of the King will show it also naturally occurs on his face.

Britannia Coin Company director Jon White said: "Once you've seen the bird on King Charles' ear, you'll zero in on it every time you see one of his coins and I suspect you'll never unsee it.

"I have no idea if Martin Jennings, the artist, intended to include this hidden image. If he did, I think it's clever and fitting acknowledgement of His Majesty's passion for wildlife and that he's listening to the plights our natural world faces.

Swindon Advertiser: The 'bird' on King Charles' earThe 'bird' on King Charles' ear (Image: Britannia Coin Company)

"These new coins already have collectors talking, thanks to the King's choice to be shown without a crown. Supposedly, he wanted to keep the design simple and without extra embellishment.

"Lots of these Charles III coins are already in circulation but they'll become more common as more are released, meaning everyone will get the chance to spot the secret bird detail for themselves."

Coins previously depicting the portrait of the late Queen Elizabeth II will now be replaced with the image of her ruling son. Coins with the new portrait are already in circulation and the new design has already been well received by admirers.

Many coins over the years have featured interesting designs and unusual features.

For example, the £1 coin featuring The Queen, which was launched in 2017, featured a number of security features to prevent cloning - including an invisible binary code that was printed directly onto Her Majesty's face that is only detectable by the Royal Mint's counterfeit coin machines.

In 2008, The Royal Mint released new coins designed by Matthew Dent which, when arranged together, create a royal shield of arms, with segments of the shield on UK 1ps, 2ps, 5ps, 10ps, 20ps and 50ps.