Sorry, burger lovers, but it looks like Burger King will not be teaming up with its competitor McDonald's anytime soon to create the ultimate fast food hamburger.

McDonald's CEO Steve Easterbrook rejected Burger King's proposal to combine its signature Whopper with the famous Big Mac into one burger as a means of promoting the International Day of Peace on Sept. 21.

According to Burger King, the burger would include elements from each sandwich, such as flame-broiled beef patty and a middle bun. It would be called the McWhopper.

Burger King said it would serve the burger mashup for a single day at a popup location in Atlanta, which is the halfway point between its headquarters in Miami and McDonald's Chicago headquarters, reports CBS Boston.

To entice McDonald's into signing on to the idea, Burger King released a full-page newspaper ad in The New York Times Wednesday, calling for a truce with McDonald's so that they can create and serve the "McWhopper," reports CNN Money. Burger King also tied in a nonprofit called Peace One Day, which promotes Peace Day.

However, McDonald's has turned the offer down.

In a Facebook post, Easterbrook said the proposal was a "great idea" and "inspiration for a good cause" but said the two companies should do "something bigger to make a difference."

"Let's acknowledge that between us there is simply a friendly business competition and certainly not the unequaled circumstances of the real pain and suffering of war," Easterbrook said.

He then offered a much vaguer proposal.

"We love the intention but think our two brands could do something bigger to make a difference," he said. "We commit to raise awareness worldwide, perhaps you'll join us in a meaningful global effort?"

He signed off, adding, "P.S. A simple phone call will do next time."

Burger King replied by stating it's open to discuss their proposal. However, "proposals like McWhopper make noise."