Burger King’s mascot, “The Burger King,” is seeking a truce, albeit temporary, with Ronald McDonald.

In full-page ads running in The New York Times and The Chicago Tribune on Wednesday, Burger King, a perennial also-ran in the burger races, has asked McDonald’s, its battered but still potent archrival, to join forces.

The goal? To operate one restaurant for one day staffed by employees of both companies and selling a burger called the McWhopper, a blend of the Big Mac and the Whopper, the best-selling burgers at McDonald’s and Burger King.

Sales proceeds would be donated to Peace One Day, a nonprofit group seeking to raise awareness of the International Day of Peace, which was established by the United Nations General Assembly in 1981 for the opening of its annual meeting.