J Lo set the record straight in a new interview with Harper's Bazaar, in which she confessed she doesn't have a brand name for the now-viral drink -- which she mysteriously referenced a full year ago in a Vogue interview -- but she described it in extensive detail.

Jen says ... "It’s just a plain orange drink. It came in a little plastic container with a little bit of aluminum foil over it. And it wasn’t called anything except orange drink or grape drink or whatever. There was an orange, a grape, and a fruit punch."

Some have suggested she's referring to Quarter Water drinks ... a staple of 20th-century childhood. It certainly matches the description she offered up anyway.

During her '73 Questions' interview with Vouge, Jenn quipped  ... "If you know, you know" -- but the running joke after that was ... nobody knew, and many accused her of making it up.

She explained at the time ... "I used to go after school and get that for like … I mean, this is many, many years ago, it was worth 25 cents, and I got it with a bag of potato chips. And that was like my after-school treat for myself."

While boomers and millennials likely know what J Lo is referring to, gen-z had a field day with her answer ... roasting Jenny for seemingly trying to be relatable/real on social media.

Jen said she saw the uproar over her "orange drink," laughing it off as "a lot of talk." Frankly, she has bigger fish to fry these days -- a la Ben Affleck -- but this is a fun little aside.