LOS ANGELES (CBSLA.com/AP) — To get you come into McDonald’s and buy new versions of its Big Mac, the chain is giving away 10,000 bottles of its trademark special sauce for people to use at home.

The move is to celebrate the introduction of the Mac Jr. and the Grand Mac, two different-sized variations of the classic sandwich.

A new-Mac-Sandwich-sizes party needs epic party favors—like 10k bottles of Special Sauce. Tomorrow find out when/where you might get one! 🎈🎉 pic.twitter.com/nbT0GVrI8l — McDonald's (@McDonalds) January 24, 2017

The giveaway is a first in the United States.

McDonald’s introduced the Big Mac in 1968. In 1975, the special sauce got its own callout in the signature Big Mac commercial, touting the burger’s components, “Two all-beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun.”

The bottles will be available Thursday between 12:30 and 2:30 p.m. at participating locations.

In Southern California, 300 Big Mac Special Sauce bottles will be given away at the McDonald’s at 201 W. Washington Blvd. in Los Angeles on a first-come, first-serve basis, and just one bottle per person. The first 100 fans will also receive a free Big Mac of their choice.

Additional details on how and where customers can get their hands on a bottle are expected to be released later Wednesday.

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