A fan tweeted the star asking her: "What the hell you get at Taco Bell? I've been tryna figure this out for the longest tine, damn."
In response, Eilish posted a video filmed in July this year, showing her order.
20 vegan tacos
In the video, Eilish is seen ordering at the drive-thru. She says: "I'm going to get 18 bean burritos with only beans, nothing else, only beans inside.
"Only beans. 18 burritos, and only beans. You know what? Make that 20."
Vegan Taco Bell
According to vegan charity PETA, there are multiple options available for plant-based diners at Taco Bell.
PETA, which has published a vegan guide to the eatery, says 'Taco Bell’s goal to cater more to animal-friendly eaters stems from its commitment to high-quality, healthy, and tasty ingredients'.
"The menu includes the Black Bean Crunchwrap Supreme, the Black Bean Quesarito, and the 7-Layer Burrito, all of which can be made vegan by simply ordering them 'Fresco style'," it says.