Burger King is offering penny Whoppers to customers, but you'll have prank one of their competitors to get it.

"The Whopper Detour" promotion allows you to order the burger through the Burger King app, but you have to be in a McDonald's drive-thru or within 600-feet of it.

The catch is that you can't actually get a Whopper at a McDonald's.

Once the order is placed you'll drive to the nearest Burger King and pick up your Whopper.

The promotion will be running until Dec. 12.