By Jonathan Davies

One of the world's biggest business rivalries, fast food rivalries at least, could be setting aside its difference to promote Peace Day.

Burger King is appealing to McDonald's to combine their flagship burgers for one day, and one day only to Peace Day, which is recognised by the United Nations and takes place on 21 September.

Burger King wants to create the McWhopper - half a McDonald's Big Mac and half a Burger King Whopper.

A co-branded pop-up stall would be created in Atlanta, half way between each fast food giant's HQs, selling the McWhopper for just one day with all proceeds going to Peace One Day, the organisation behind Peace Day.

The McWhopper would be six parts Big Mac - the top bun, burger, cheese, lettuce, special sauce and middle bun - and six parts Whopper - tomato, onion, ketchup, pickles, burger and bottom bun.

"Let's end the beef, with beef," Burger King said in its announcement.

"If [McDonald's] chooses not to participate, no harm done — after all, peace isn’t always easy to achieve.

"Should they say yes, burger fans will get to experience the culinary mash-up of a lifetime and walk away inspired by the mouth-watering taste of peace."

McDonald's is yet to respond to the proposal.