J. Lo workout-top sold out almost instantly after teaching Jimmy Fallon how to Tik Tok

Jennifer Lopez was one of the first people to wear the highly anticipated New Balance x Staud collection.

While teaching Jimmy Fallon how to TikTok, Lopez wore the sports bra that has a genius hidden feature: a zipper right across the chest.

It's perfect for storing your cell phone or hiding a tiny bottle of liquor.

The options are really limitless, which is probably why it's impossible to find it anywhere.

While the leggings are still available in limited sizing, the top unfortunately is not available in any size at all.

[Source: instyle.com]