If you’ve been on Facebook or Twitter this week, you’ve probably come across Gradient, the popular, new photo app that takes a picture of your face and tells you what celebrity you look like. After being available for barely a week, the app has been downloaded more than 1 million times.

Like many other sudden phenomenons, the app might not be exactly what it looks like at first glance. After FaceApp went viral despite having a questionable approach to privacy, you likely want to be careful when you share your face. Here’s what you need to know about Gradient:

Gradient is essentially a photo-editing app. Similar to VSCO and Faceapp, the app allows you to edit pictures.

The app went viral because of its You Look Like … feature, which takes your photo and then transforms it through a four-step transition into an image of a celebrity.

The app is brand new, but it’s already the No. 1 photo and video app in the App Store.

Gradient is the work of a developer called Ticket To The Moon, Inc., and is the first app to be released by the company.

There’s not a ton of public information about Ticket To The Moon, which lists its address as being in Las Vegas. According to Gizmodo, it shares an address with Chinese investment firm Meihua Capital Partners.

Gradient went viral thanks to a handful of celebrities using the app and posting their results to Instagram. Based on their use of the hashtag #ad, it looks like the Kardashian family was paid to endorse the app on social media, so Instagram Story posts from the app by Kylie Jenner, Kim Kardashian, Kourtney Kardashian, and Khloe Kardashian are all paid placements, Newsweek notes.

Some users have commented with concerns that Gradient might go the way of FaceApp and transform from a viral sensation to a security concern overnight.

While the app doesn’t require you to sign off the rights to your face like FaceApp did, it is a bit shady when it comes to subscriptions.

In order to upload a picture to the app and get that sweet celebrity selfie, you’ll need to “UNLIMIT yourself” by purchasing a subscription for $4.99 a week or $19.99 a month. Yes, there’s a free 3-day trial, but you’re going to be locked into an auto-renewing subscription after that free trial ends. If you forget to cancel — and let’s face it, lots of people do — you’ll keep getting charged.

Even better, Gradient requires you to cancel it 24 hours before that 3-day trial is over if you don’t want to be charged. For a lot of users, that’s going to mean at least a $4.99 charge on their account.

When it comes to privacy, Gradient doesn’t claim to own your face photos, but does say under its terms of service that it can use the photos essentially however it wants.

“Gradient does not claim ownership of Your Content that you upload or stylize through the Service,” the terms say. “You hereby grant to Gradient a non-exclusive, fully paid and royalty-free, transferable, sub-licensable, worldwide license to use Your Content to provide our Service, subject to the Privacy Policy.”

We’ve reached out to Ticket to the Moon for clarification on the app’s privacy policy and will update this story when we hear back.

You can view the full terms of service for the app here.