McDonald's is testing a new Big Mac recipe for the first time in history

McDonald's is changing the recipe for the iconic Big Mac for the first time in 50 years.

The fast-food chain is adding a spicy Sriracha sauce to the burger at 126 restaurants in Columbus, Ohio.

McDonald's spokeswoman Becca Hary called the move a "milestone for McDonald's."

She said customers in the area will also be able to test the Sriracha Mac sauce separately for dipping McNuggets and fries.

The traditional Big Mac consists of two 1/10-pound burger patties, three pieces of bread, and two slices of cheese, special Mac sauce, lettuce, pickles, and onions.

If the test goes well, McDonald's will start offering the Sriracha Big Mac nationwide, the company said.

The addition of the Sriracha sauce marks the first flavor change that McDonald's has made to its iconic Big Mac. But it's the second time this year that the company has tinkered with the sandwich.

The chain is launching a smaller "Mac Jr" and a larger "Grand Mac" nationwide for a limited time in early 2017 after testing the sandwiches earlier this year.

The Mac Jr. is a miniature version of the Big Mac with a single 1/6-pound burger patty.

The Grand Mac features 66% more beef than the regular Big Mac, an extra slice of cheese, and a larger bun.