The egg, from the extinct Elephant Bird, is 30 centimetres high and 21 centimetres wide.
Elephant Bird eggs are the largest the world has ever seen - and this egg is expected to fetch up to $44,000 when it goes up for auction.
'It's the perfect timing - Easter - it's the largest Easter egg, in fact the egg is the largest egg ever laid by any animal, they are bigger than dinosaur eggs,' Scientific Specialist James Hyslop told Reuters.
He also joked the egg would have made 'one very big omelette' - it is around 120 times the size of a chicken egg.
The egg was laid in Madagascar and is thought to have been discovered by archaologists in the late 19th or early 20th century.
The species became extinct sometime between the 13th and 17th centuries.
It is thought the bird, which is the largest bird ever to have lived, was hunted to extinction.
The auction will take place on April 24.
A giant egg from the extinct Elephant Bird which is incredibly rare is up for auction at Christie's in London.
Elephant bird eggs are the largest the world has ever seen, even larger than dinosaur eggs.
The egg, which is 30 centimetres high and 21 centimetres wide (12 inches and 8 inches), is expected to fetch up to 30,000 pounds when it is sold at the end of the month.
"It's the perfect timing - Easter - it's the largest Easter egg, in fact the egg is the largest egg ever laid by any animal, they are bigger than dinosaur eggs," said James Hyslop, Scientific Specialist at Christie's.
The egg was laid by the giant Elephant Bird in Madagascar. The species became extinct sometime between the 13th and 17th centuries. It's thought that this rare, complete sub fossilised egg would have been discovered by archaeologists in the late 19th or early 20th century.
It is so enormous it dwarfs an ordinary chicken egg and is around 120 times the size.
Hyslop joked that it would have made "One very big omelette."
The Elephant Bird was the largest bird ever to have lived. Resembling a heavily-built ostrich, it would have stood up to 3.4 metres (11 feet) high. It is thought the bird was hunted to extinction.
The auction takes place in London on April 24.
