McDonald's just revealed its biggest burger

McDonald's is launching a new burger that will be even bigger than the Quarter Pounder. 

The chain is adding a Sirloin Third Pounder to the menu, with patties that weight about 1.3 ounces more than the Quarter Pounder. 

The limited-time sandwich will cost $4.99 in most markets, the AP reports. 

Some restaurants in the New York area have already begun offering the burgers, which have the biggest beef patties on the menu, according to posts on social media.

The sandwich is apparently served on a wooden paddle. 

The burgers come with lettuce and tomato, bacon and cheese, or Steakhouse style, which has grilled mushrooms, onions, white cheddar cheese and peppercorn sauce.

The new sandwich is the biggest burger on McDonald's menu since 2013, when the chain retired the Angus Third Pounders following a four-year run.