(NBC) - The fast-food chain Burger King is selling its iconic Whopper for just a penny at McDonald's.
It's all part of a new BK promotion called the "Whopper Detour" to get customers to use its re-launched app.
To get the deal, customers must place their order within 600 feet of a McDonald's location.
The app will determine your location and then unlock the Whopper deal.
And once the order is placed, the app will lead customers to the closest Burger King.