Fat Brands is going to have to loosen its belt after this acquisition.

The parent company of popular burger chain Fatburger saw its shares skyrocket more than 200 percent after it announced that it would be acquiring fellow burger slinger Johnny Rockets.

The $25 million deal will see it add 700 locations of the 1950s-themed restaurant — famous for its hand-spun shakes, chrome decor and singing waiters — to its portfolio, and is expected to be completed in September.

Fat Brands’ CEO Andy Wiederhorn said the company expects to modernize Johnny Rocket’s menu, which already has a black bean burger, by adding plant-based options and vegan milkshakes. While Fat Burger is a fast food restaurant, it’s food is made to order.

The deal comes as restaurants nationwide deal with greater restrictions on their operations due to the coronavirus, including a ban on indoor dining in many large cities like New York City.

But Fat Brands’ Wiederhorn said he’s betting consumers will quickly return to casual-dining operations like Johnny Rockets once the pandemic subsides. “If working from home becomes a bigger component of daily life, that just adds to the demand to be able to socialize in some way,” he told the Wall Street Journal.

Fast-casual restaurants in some markets are already benefiting from a surge in demand for outdoor dining and home deliveries, Wiederhorn added.

Shares of Fat Brands were up 204.5 percent in early morning trading Thursday, at $10.75.

With Post wires.