Months after Burger King started serving a plant-based version of its signature Whopper, McDonald’s announced Thursday that it is rolling out its own veggie burger.

The “P.L.T.” — that’s an acronym of its ingredients, natch: “Plant. Lettuce. Tomato” — will be available for 12 weeks starting Monday at 28 locations in southwestern Ontario, according to a statement. The burger in question is from Beyond Meat, a company whose meat-substitute patties are already being served Carl’s Jr. locations around the United States.

The alliance of market-dominating McDonald’s and Beyond Meat puts them in competition with the combo of Burger King and Impossible Foods, the provider of the Whopper’s vegetarian patty. Burger King tested its Impossible Whopper in the St. Louis area before expanding it to the chain’s 7,200 locations nationwide. McDonald’s is describing the P.L.T. in similar terms. “This test allows us to learn more about real-world implications of serving the P.L.T., including customer demand and impact on restaurant operations,” Ann Wahlgren, McDonald’s vice president of global menu strategy, said in the statement.

Beyond Meat, which is also available in grocery stores, reformulated its burger this summer, making it more attractive, with a meatier look and taste. It seems McDonald’s will be customizing the ingredient: The Beyond Meat patty is “crafted exclusively by McDonald’s, for McDonald’s, to deliver the iconic taste customers know and love,” per the statement.

In addition to the aforementioned lettuce and tomato, it also includes a slice of cheese, onion, mustard, ketchup and a “mayo-style sauce,” served on a sesame-topped bun. It clocks in at 460 calories, 25 grams of fat and 920 milligrams of sodium — all less than those in the company’s Quarter Pounder and Big Mac. The price is $6.49 Canadian, or about $4.89 U.S.

The P.L.T’s debut follows another late entry from McDonald’s in the ongoing fast-food wars. Last week, it began serving a spicy chicken sandwich whose entry trailed that of the Popeyes viral version, which lit up social media this summer and resulted in a nationwide shortage. But it’s not the first time Burger King has paved the way for its rival: As my colleague Tim Carman noted when Burger King’s veggie option came out, McDonald’s founder Ray Kroc had acknowledged that the Big Mac was the culinary clapback to the Whopper.

The news that McDonald’s was getting into the veggie-burger game was met with cheers on social media, with many people lamenting that the small test market meant they wouldn’t be able to get their hands on one anytime soon. Also enthusiastic? Investors. Shares of Beyond Meat rose 12 percent, while McDonald’s stock was up 1 percent, CNBC reported.

More from Voraciously:

McDonald’s is tardy to the chicken-sandwich party with a spicy entry that can’t touch Popeyes’

The key to White Claw’s surging popularity: Marketing to a post-gender world

We did it, America. We ate Popeyes out of chicken sandwiches.