Burger King is celebrating their newly revamped mobile app by offering Whopper sandwiches for just one-cent each – but you’ll have to go to a McDonald’s restaurant first in order to score the deal.

Here’s how the deal works: For a limited time, when you go within 600 feet of any McDonald’s restaurant, the newly revamped BK mobile app will unlock the Whopper for a penny promotion, in what the brand is calling the “Whopper Detour.”

Once unlocked, simply place your one-cent Whopper order and the app will direct you to the nearest Burger King restaurant to pick up your order. The Whopper Detour works by geofencing McDonald’s locations across the country.

The Whopper Detour promotion can be redeemed one time only per app user through December 12, 2018, at participating locations nationwide.

Image – Burger King