McDonald's nostalgia-heavy restaurant spinoff has got fast food fans waiting anxiously for an official debut date.

Announced by McDonald's CEO and president Christopher Kempczinski during the company's second-quarter earnings call in July, the new limited chain, titled "CosMc's," is set to unveil in limited locations in early 2024.

Seemingly capitalizing on nostalgia, a move that has proven fruitful for the chain in recent months, the restaurants will have theming inspired by an alien character named "CosMc" who appeared in McDonald's commercials and advertisements from 1986 to 1992.

However, one curious patron who stumbled across a yet-to-open location in Illinois may have managed to get the internet a quick sneak peek of what is to come.

Here's what we know so far about the galactic new venture.

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What is CosMc's?

CosMc's is a new spinoff restaurant idea from McDonald's. Kempczinski described it as "a small format concept with all the DNA of McDonald’s but its own unique personality."

It seems the company plans to lean into the space-based, futurism-of-the-past aesthetic associated with CosMc's character from the late '80s and early '90s. McDonald's has had success with the nostalgia market lately, having rolled out adult Happy Meals last year before reintroducing the Hamburglar in April and Grimace in June with a special birthday meal and a purple shake.

When does CosMc's open?

While an exact opening date has yet to be shared by the company, Kempczinsk initially said more information will become available at the company's Investor Day at the end of the year. For now, fans are stuck with a loose launch date of early 2024.

Who is the character CosMc?

As previously reported by USA TODAY, CosMc hasn't appeared in the McDonald's universe in more than 30 years.

As previously described, a 1987 commercial called "The Story of CosMc," is available via the YouTube archives and includes Ronald McDonald and Grimace, who come across a strange object that's landed in McDonaldland. Hands and a head clad in a silver suit pop out and CosMc (pronounced Cosmic) appears, saying he "popped in from outer space on a trade mission."

After making a series of perhaps undesired trades with the other characters to get his hands on a cheeseburger and some fries, CosMc is summoned back with a giant magnet by Ronald before settling in for a picnic with the others.

A round, googly-eyed orange character, CosMc looks alien-like with two antennae placed on top of his head and a chrome space suit complete with multiple sets of arms sticking out of each side. He can even fly courtesy of his space suit.

McDonald's has yet to make clear if the mascot itself will return to restaurants as part of the concept launch.

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What is on the CosMc's menu?

McDonald's has not announced what will be on the CosMc's menu. However, Chicago-area real estate investor Iman Jalali claims to have captured images of a menu board outside an upcoming CosMc's in Illinois. The photos were shared on social media and obtained by USA TODAY.

According to the photos, the drive-thru menu features teas and lemonades, coffees, slushies and frappes and signature fruit drinks called "Galactic Boosts." Drinks like a Turmeric Spiced Latte, Churro Frappe and Sour Cherry Energy Burst are some of the items listed.

Food items included a Spicy Queso Sandwich, a Creamy Avocado Tomatillo Sandwich, Pretzel Bites and Savory Hash Brown Bites. The list appears to also bring back all-day breakfast with classic items like the Egg McMuffin, Bacon McMuffin with Egg and Sausage McMuffin with Egg. Traditional McFlurry flavors also made an appearance.

Jalali said the photos were taken in Bolingbrook, a town roughly 30 miles outside of Chicago, where the first CosMc's is set to open. While passing by what was once a Boston Market, he noticed the shiny new four-lane drive-thru complete with digital menus. Interested to see more, Jalali said he approached the location to see a team of actors and cameras filming a commercial, meaning he was only able to snap a few photos from a distance.

Jalali was unable to glean any further information and McDonald's did not immediately respond to the request for comment from USA TODAY. It is unclear if all or any of the items on the board are intended to be served upon launch.

Reporting contributed by Mike Snider, USA TODAY.