This probably isn't what the United Nations had in mind when it established the International Day of Peace: Burger King is asking McDonald's to join forces to create a 'McWhopper'.
In full-page newspaper ads yesterday, Burger King says it's calling for a truce with McDonald's so that they can create a "mash-up" of their most famous burgers - the Big Mac and the Whopper.
Burger King says it wants to serve the concoction for a single day at a pop-up location in Atlanta, a midway point between the headquarters of the two chains.
Burger King is tying the publicity stunt to a non-profit body called Peace One Day, which says it promotes Peace Day. The UN created the International Day of Peace in 1981 to coincide with its annual opening session in September.
It then designated September 21 as the annual "day of non-violence and ceasefire" in 2001.
In a comment posted on its Facebook page, McDonald's CEO Steve Easterbrook said the proposal was inspiration for a good cause, then took a dig at the ploy by Burger King. "Let's acknowledge that between us there is simply a friendly business competition and certainly not the unequalled circumstances of the real pain and suffering of war," Mr Easterbrook said.
The proposed mash-up of the Big Mac and Whopper would include elements of each, such as flame-broiled beef patty and a middle bun, according to a website Burger King set up. Burger King notes on the site that it's open to discussing the proposal.