Instagram users reported Wednesday they lost thousands of followers overnight and at least two celebrities may have lost millions. Instagram said it's investigating the "issue." 

In a tweet on Wednesday morning, Instagram said, "We're aware of an issue that is causing a change in account follower numbers for some people right now. We're working to resolve this as quickly as possible."

The social media platform did not say what caused the issue. 

As soon as they realized what happened, Instagram users started tweeting. Some indicated the vanishing act happened in a matter of seconds.

"Who else lost 20,000 followers on ig today?" tweeted Wil Dasovich.

"anyone else lose hella followers on IG at once? I lost 32k in seconds?" tweeted Princeton Perez.

Eagle-eyed fans noted that singer Ariana Grande lost 3 million followers.

And Selena Gomez lost 2 million. The singer was the second-most followed person worldwide on Instagram last year.