Over the weekend, Reddit sleuths discovered that dark mode had been added to the Facebook Messenger app. But rather than just putting the option in the settings menu, Facebook tasks you with sending the crescent moon emoji in any chat, at which point a bunch of moons will fall from the top of the screen and you’ll be presented with a prompt to turn on the “dark Messenger background.” Tapping the pop-up will take you straight to settings.

Dark mode is accessible to Messenger users around the world on iOS and Android devices, but for now, you will have to use the trick above to enable it. In the coming weeks, the setting will be available from the settings menu, so if you don’t want to send a moon emoji to anyone, you can just wait until dark mode is fully rolled out.

“Messenger’s dark mode provides lower brightness while maintaining contrast and vibrancy,” reads the description from Facebook’s 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.”

This is the first time any of Facebook’s platforms have allowed users to activate dark mode. It’s unclear whether or not the main Facebook app will also gain dark mode at some point, but depending on the general reaction to the feature in Messenger, it might be coming soon as well. Messenger 4, the latest update for the popular chat app, has received a mix reaction overall, but dark mode is sure to be a winner.