Global fast food giant McDonald’s Corp. (MCD.N) has filed a trademark infringement notice in Australia after the local unit of Burger King created a similar product called the “Big Jack,” according to a local newspaper report on Thursday.

Australian franchise Hungry Jack’s released a double layer hamburger in July, similar in construction and appearance to the Big Mac, McDonald’s alleges in documents filed with the Federal Court on Aug. 28, the Sydney Morning Herald newspaper reported.

Hungry Jack’s “deliberately adopted or imitated” the “distinctive appearance or build” of the Big Mac, along with its ingredients and tagline; “two all-beef patties, special sauce, lettuce, cheese, pickles, onions – on a sesame seed bun”, McDonald’s alleged, according to the report.

Hungry Jacks markets the burger online as comprising “two flame-grilled 100% Aussie beef patties, topped with melted cheese, special sauce, fresh lettuce, pickles and onions on a toasted sesame seed bun”.

The apparent similarities were picked up by plenty of social media users including one Twitter user named Gino, who tweeted “Big Jack = Big Mac! Naughty naughty!”

A McDonald’s Australia spokeswoman said it would not be appropriate to comment given the matter was before the court.