Days after Facebook Messenger’s dark mode was outed on Reddit, the social network has made the update official for iOS and Android. For now, you can only enable it by sending the crescent moon emoji in an existing chat thread or new message.

It’s one of Facebook’s most clever tactics to get users actively chatting – instead of simply activating the mode via settings – at a time when it’s facing increased competition from rivals like TikTok.

Messenger is also the first of Facebook’s social apps (which span its eponymous social network, Instagram and WhatsApp) to officially get a dark theme. “Messenger’s dark mode provides lower brightness while maintaining contrast and vibrancy” Facebook writes in its blog post.

“Dark mode cuts down the glare from your phone for use in low light situations, so you can use the Messenger features you love no matter when or where you are.” It’s promising to make the feature accessible via the settings tab in the near future.

Messenger’s dark mode was made available to select users in certain countries late last year as part of the feature’s early testing phase. Now, it’s available to everyone who has the latest version of the app installed on their devices.

To unlock dark mode in Messenger, you must first send a message to someone you know (or even yourself) that consists solely of a crescent-shaped moon emoji (the one that looks like this: ☽).

Once you’ve done that, several moon emoji will rain down over your conversation screen, letting you know that the feature has been unlocked and can be toggled on or off within the app’s settings menu.

Some users have reported instances of a pop-up window that will inform you of the new feature, though it appears that it doesn’t happen for everyone.

Facebook teased dark mode in October 2018 and tested it in a few regions back in January, but now it’s widely available.

The company didn’t immediately respond to a request for comment on the new feature.