Big Mac, a flagship McDonald’s sandwich that made its debut in Uniontown, Pennsylvania, in April 1967, now has a new chicken variant, writes Roshan Fernandez for The Wall Street Journal.

After proving to be a hit in the Keystone State, McDonald’s added the double burger sandwich to the chain’s national menu in 1968.

Last week, McDonald’s decided to make one of the biggest riffs on the decades-old burger. They rolled out a Chicken Big Mac at its restaurants across the country.

The essence of the sandwich remained the same. The only two differences are two tempura-battered chicken patties instead of beef and the lack of onions.

“This one is really about when we heard from our fans and the consumer research,” said Wayne Kuhl, a senior manager working on the chain’s U.S. menu.

While this is the debut of the Chicken Big Mac in the U.S., the sandwich has already been available on a limited-time basis in several other markets, including the U.K., Canada, and Australia.

The new Big Mac variant will be available for a limited time at participating locations.

Read more about McDonald’s new chicken Big Mac variant in The Wall Street Journal.