ST. LOUIS (KTVI) – McDonald's locations in the U.S. will introduce a new sandwich this fall — one that puts a twist on one of the chain's signature burgers. After appearing on select menus in a number of international markets, the Chicken Big Mac will be making its debut in the States starting Oct. 10. The new Chicken Big Mac debuts nationwide on Oct. 10. (McDonald's) The sandwich, described as "not not a Big Mac" by McDonald's, is essentially built the same way as the Big Mac, albeit with two "tempura-battered chicken patties" in place of beef. “With the introduction of the Chicken Big Mac, we’re excited to pay homage to one of our most iconic menu items, the Big Mac, and introduce it to a whole new generation of fans,” Tariq Hassan, the chief marketing officer at McDonald's, was quoted as saying in a press release. These are the fastest, most satisfying fast food chains: new study Foodies in Los Angeles, meanwhile, were treated to an early taste of the Chicken Big Mac last weekend — whether they were aware of it or not. McDonald's had secretly organized a pop-up restaurant called McDonnell's to serve its "chicken sandwich" to unsuspecting(?) guests. "Fans were loving it, some even called it a McDonald’s dupe — and in a plot twist as sweet as our Apple Pie — McDonald’s was behind it all," the company explained. The Chicken Big Mac will be available for a limited time at participating locations while supplies last.