'Scarlett Johansson' hen's round egg sells on eBay for £480

Kim Broughton (left) will donate the money raised from the egg's sale to the Cystic Fibrosis Trust

A "perfectly spherical" chicken egg has sold for an "unbelievable" £480 on the internet auction site eBay.

Kim Broughton found one of her hens - now renamed Ping Pong - had laid the round egg in her garden in Latchingdon, Essex, on 17 February - Pancake Day.

She decided to auction the egg in aid of the Cystic Fibrosis Trust after a friend's son died from the disease.

Ms Broughton, 44, said she imagined the buyer was interested in preserving, rather than eating, the unusual egg.

The item, laid by a Buff Orpington hen - described as the "Scarlett Johansson of the chicken world" - attracted 64 bids, but the identity of the winner is not yet known.

Ms Broughton said she had been tempted to cook and eat the egg before being told it was "one-in-a-billion".

The "perfectly spherical" egg was laid by an Essex hen who has since been renamed "Ping Pong"

She said: "I was literally about to crack it open to make a pancake when a mate saw the photo I put on Facebook and messaged me to say 'Don't do it!'

"Apparently somebody had sold one before for more than £90 so I thought 'Great if I can sell if for that'.

"When it was at £20 I thought 'Who'd pay that for an egg?' and then it went through the roof. It's unbelievable".

"I'm so happy as the cause is so close to my heart," said Kim Broughton

Ms Broughton, who said she was known as "the mad chicken woman", said she was nervous about sending the egg through the post.

"At the moment it's safely in my son's lunchbox padded with kitchen roll - but if I send it in a hard box it should be quite safe," she said.

Speaking to BBC Essex Ms Broughton said she would be keeping a close eye on future eggs in the hope of raising "a few more quid" for the charity.