McDonald’s is helping its fans celebrate one of the restaurant’s favorite holidays: National French Fry Day. Tomorrow, customers can score one free order of any size McDonald’s World Famous Fries® exclusively in the McDonald’s mobile app, no other purchase necessary.

National French Fry Day is celebrated annually on July 13th. As a brand known for its iconic French fries, McDonald’s is proud to join in the festivities and give back to its loyal customers.

In honor of the big day, here are some facts about McDonald’s World Famous Fries®.

  • Fries were among the very first items available on the original menu at McDonald’s Founder Ray Kroc’s first restaurant in Des Plaines, Illinois which opened in 1955.
  • In the 1960s, McDonald’s patented the French Fry scoop, a device that allows crew to grab and bag the perfect amount of fries every single time. You can still find them in restaurants today.
  • McDonald’s has a list of approved potatoes that meet its standards.  In the U.S., McDonald’s most recently added the Dakota Russet to its list after it passed a rigorous testing process.
  • McDonald’s fry-cooking process is basically an art form.  Everything from the fry time to the amount of salt is carefully measured so that the fries are right every time.

To take advantage of this limited-time offer, customers simply need to download the McDonald’s app and navigate to the “Deals” section. From there, they can find the National French Fry Day promotion and redeem their free French fry at any participating McDonald’s restaurant on July 13.

The McDonald’s app is available for download in the Apple App Store and the Android Google Play Store. With the McDonald’s app, customers get access to exclusive deals, they can order ahead and pass the line with Mobile Order & Pay, plus they can join MyMcDonald’s Rewards to earn points on every order to redeem for free McDonald’s.