TGI Fridays is going to start delivering booze - and it could help defeat a curse sweeping the restaurant industry

TGI Fridays wants to give customers the chance to chug the chain's margaritas from the comfort of their own couches. 

On Thursday, Fridays announced it had partnered with the delivery startup Lash to begin delivering alcoholic beverages along with food orders placed via the chain's mobile app. The test will begin in Houston and Dallas, Texas, in the coming months and will begin to roll out across the US in 2018. 

"We're a bar-centric business," Caroline Masullo, Fridays' vice president of digital strategy, told Business Insider. "Right now, no one - from within their own technology - is delivering both food and alcohol." 

To-go and delivery sales are a rare bright spot in the casual dining industry right now, with Fridays growing take-out sales by 30% since launching online ordering last summer.

Booze is also crucial to TGI Fridays' strategy. The chain has recently emphasized its history as a bar as millennial interest in sit-down casual dining chains has withered.

However, delivering alcohol is a legally tricky proposition. TGI Fridays and Lash came up with a solution that will be tweaked on a state-by-state basis (what Masullo calls a "block-by-block" strategy) to follow local ordinances. 

While food and alcohol will be delivered together when ordered on TGI Fridays' app, the delivery person is actually making two stops: first at the liquor store, second at Fridays.

For cocktails, you can order an "everything but the booze" kit (which is sold by Fridays), plus the suggested bottle of liquor (sold by the local liquor store). Then, you mix the drink yourself at home. Fridays is also exploring the possibility of making bartenders available for hire via the app.

Here's a video showing exactly how the process works: 

TGI Fridays' booze delivery plan is a bit complicated behind the scenes. But, the chain hopes that it can help drive incremental sales and stand out from the "sea of sameness" in the sit-down restaurant business. 

Casual dining chains including Applebee's, Buffalo Wild Wings, and Ruby Tuesdays are facing slumping sales and store closures. Factors including millennials' indifference to casual dining classics and the rise of fast-casual chains have played a role in their downfall. 

As a result, many chains have doubled down on aspects of their business that they hope will differentiate them from the competition. Applebee's wants to win back Baby Boomers, while Chili's has revamped its menu to refocus on burgers and ribs.

Now, TGI Fridays is betting on delivery and booze - together and apart - to win over customers.