It's common for clothing trends to come, go and be rediscovered by future generations — but Gen Z's adoration over their newest "vintage" find is making some millennials feel old already.

Teens on TikTok are proclaiming their love for "flared leggings," the comfortable, formfitting black stretch pants that flare out at the ankles that millennials know as "yoga pants."

"Can’t believe the tik tok teens have just discovered yoga pants and they’re calling them flared leggings," wrote one Twitter user in a post that has since gone viral. "I hate it here."

can’t believe the tik tok teens have just discovered yoga pants and they’re calling them flared leggings I hate it here

On The Zoe Report's TikTok, from the website of celebrity stylist Rachel Zoe, one contributor shared a video of herself trying on the former wardrobe staple, saying that she had purchased a pair after seeing another influencer wearing them. In the 20-second clip, she tries on the pants and seems to be delighted with the fit, writing "Get themmmm!" at the end of the video.

The clip was later shared on Twitter.

"I regret to inform you all that the teens are bringing yoga pants back, but they’re calling them 'flared leggings,'" Twitter user Taylor Loren wrote.

I regret to inform you all that the teens are bringing yoga pants back, but they’re calling them “flared leggings” pic.twitter.com/ppyAmIhINU

Another TikToker said that she bought a pair of the pants from Old Navy, calling them "so cute!" in a short video.

On social media, the reactions came fast. Some said that they hadn't even realized that yoga pants had become "old."

gen z calling yoga pants ‘flared leggings’ is stressing me out like.... they’re not that old? i swear i still wore them in like 2013?

"I swear I still wore them in 2013," wrote one user.

ok so just learned gen Z says yoga pants are back in style but they call them ...... FLARE LEGGINGS!!!!!! i’m sick how old m i

Others said that while Gen Z may have rediscovered the pants style, they're wearing them much more fashionably than their predecessors: gone are the chunky animal-print waistbands, the shin-high Ugg boots and the graphic T-shirts that defined plenty of middle school wardrobes. (Unless those make a comeback of their own!)

I did not wear the Pink zebra yoga pants in middle school for y’all to call them “flared leggings”

Y’all just now discovering “flared leggings” aka yoga pants... you ain’t seen nothin’ yet.... pic.twitter.com/CriGXvYFKF

Seeing lots of “flared leggings” when it’s actually called yoga pants. Tucked into ugg boots. Respect your elders.

i can’t with (young) gen z calling yoga pants “flare leggings” 💀🤣 like we didn’t have 10 different pairs with badazzled w animal print from victoria’s secret

Some joked that they'd already "paid (their) dues" with the look and couldn't bear to have them resurge in popularity.

All I’m saying is I’ll die before I partake in the “flared leggings” trend. I payed my dues in my Justice fold-over-band yoga pants.

for the love of ALL THAT IS HOLY they're YOGA PANTS. i did NOT watch everyone i know go through a phase where we thought the victoria's secret thick banded yoga pants were the epitome of fashion to watch a bunch of people born like 4 years after me rebrand them as flared leggings

One user said that the popularity of the new term is just another sign that 2020 is the worst year ever.

I didn’t think 2020 could get worse until the 1. People are bringing back yoga pants and 2. calling them flare leggings 😖😖😖

But it's not all Gen Z's fault. Plenty of retailers, including H&M and Amazon, are selling the pants with the new name.

To be fair the retailers are calling them flared leggings

You can get them from Amazon if you type in “flared leggings” I checked lily lemon and they’re like $98 🥴 pic.twitter.com/4PnAFyk2QO

H&M is calling yoga pants flared leggings too I’m crying pic.twitter.com/zL28INMRP9

No matter what you think of the style, everyone seemed to agree on one point: If these pants are cool again, does that mean we can go back to wearing the stretchy staple every day?

Kerry Breen is a reporter and associate editor for TODAY.com, where she reports on health news, pop culture and more. She holds a master’s degree in journalism from New York University.