A secret from a McDonald's in United Kingdom has been revealed: a "secret menu" does exist, according to an anonymous manager from the big fast food chain, reports stated.

A secret menu would allow customers to place an order for a creative version of their standard meals.

The menu includes meals called "Poor Man's Big Mac" and "McGangbang," according to Stuff NZ.

The existence of such menu was revealed by a 24-year-old manager from Scotland in a Reddit post, under the username orchidhibiscus.

The secret menu means that customers can add or remove any ingredients from the standard meals through a special request. These orders are referred to as "grill orders."

The anonymous poster did point out that the "secret menu" was not invented by McDonald's and even the fast food chain's employees don't have any idea about them.

Customers simply need to explain what they want and should be willing to pay for them.

Mashable contacted McDonald's to make a comment on the claims of a "secret menu," but the company responded that they don't have anything of that sort. However, they confirmed that customers can customize their orders.

A spokesperson for McDonald's said that a secret menu does not exist in McDonald's UK because the food is already amazing enough to be kept a secret.

"Any requests for extra items or changes to our products are considered at the restaurant manager's discretion and any additional items may be charged for," the spokesperson added.

Secret menus started to become popular in April when HacktheMenu had put up a complete list of grill orders not only from McDonald's, but also from a number of fast food chains including In-N-Out, Taco Bell, Chipotle, and even beverage chains like Starbucks.

People who want to attempt to order a meal from a secret menu should expect that most of the time, staff will not have any idea about a meal variation.