The social media platform - which launched the dark mode for its desktop interface last month - is looking into rolling out the feature for mobile users.
A spokesperson told The Verge that the company has made the feature available to a very small percentage of people globally.
According to the Facebook representative, the mobile version of the dark mode introduced for desktop last month is "meant to cut down on glare".
However, there is currently no timeline on when the feature will be made available to all mobile users.
The update comes after Facebook launched a Messenger desktop app - which is available on the Mac App Store and Microsoft Store - to allow users to message friends and start video calls.
The platform also launched a dark mode as part of Facebook's move to roll out the feature across its platforms.
The company said at the time: "Now more than ever, people are using technology to stay in touch with the people they care about, even when physically apart.
"Over the past month, we saw more than a 100% increase in people using their desktop browser for audio and video calling on Messenger.
"Now with apps for MacOS and Windows, the best of Messenger is coming to desktop, including unlimited and free group video calls."
Facebook has hyped up some of the best features including on the service include group videos on a larger screen, notifications, chat sync across mobile and desktop, multitasking, Dark Mode and GIF support.