The Oklahoma-based fast food chain is promoting its new Creamery shakes, which were introduced last month, at the music festival using Instagram, AdWeek reports. For one day only on April 16, festival-goers will be able to order a Sonic Creamery milkshake through the social media platform and “pay” simply by posting a picture to their Instagram accounts.

Sonic enlisted the help of the Instagram-famous Chef Jacques La Merde—who only recently revealed her real identity as Christine Flynn, executive chef at Toronto’s iQ Food Co.—to design square shakes specifically for Instagram. She’s known for using junk food, like Doritos and Hostess cupcakes, to make dishes that look like they could be served at a high-end restaurant. “She is someone who pokes fun at fine dining by styling and photographing more appraochable foods in super sophisticated ways,” Sonic president and chief marketing officer Todd Smith told AdWeek. “When we approached her with this idea, she said, ‘Oh that’s so cool, that’s exactly what I do.'”

https://www.instagram.com/p/BDx3ipCR43J/?taken-by=sonicdrivein

Smith added that Sonic wanted to be the first brand to design a product specifically for Instagram. Everything about the shake is square, from the straw to cherry on top. “I thought it was visually super interesting,” Margaret Johnson, executive creative director of Sonic agency Goodby Silverstein & Partners, told AdWeek. “We all take pictures of our food and post it. It seemed like a fun extension of pop culture that’s already happening.”

This promotion is meant to help Sonic appeal to a younger audience, which can be found both at Coachella and on Instagram. The chain currently has 118,000 followers on the platform—meager compared to other fast food establishments and even independent, food-focused Instagram accounts. Sonic did something similar a couple of years ago when it promoted a new slushy flavor with a limited-time-offer on Snapchat.