People will need a Facebook account first to sign up for Messenger from now on.
The advantage of using messenger only with phone numbers, which the social network provided its users from 2015, will not be available anymore, reports Engadget.
Now, an entry in the website's Help Center clearly states that "you'll need to create a Facebook account to use Messenger."
The company has also confirmed the change to VentureBeat, telling the publication that "the vast majority of people who use Messenger already log in through Facebook" and that it merely wants to simplify the process.
The spokesperson also said that the new rule applies to those "new to Messenger," and that those already using the app without an account don't need to do anything.
However, some users have complained of encountering difficulties signing in after the transition -- the app apparently kept telling them that their account has been restricted.
It's unclear if the change will have any effect on the tech giant's plan to make its messaging products interoperable, which will allow users to send messages across Messenger, Instagram and WhatsApp.
A lot of people use WhatsApp, in particular, for the privacy and security it provides.