(CNN) -- Burger King is trolling its biggest rival with a promotion available through the Burger King mobile app. For a limited time, you can order a Whopper for a penny, but you can only do it near a McDonald's.
Sound confusing? It's actually pretty simple.
All you have to do is get within about 600 feet of a McDonald's and use Burger King's "BK" app to order a Whopper. Then, drive to the nearest Burger King and pick up your sandwich - for just one cent.
The promotion is called the "Whopper Detour" and runs through Tuesday, December 12th.
Burger King launched the promotion with a video showing people trying to pick-up their Whoppers at McDonald's drive-through windows.