The theme, which was already available on Facebook's Messenger, comes as part of an effort to make the messaging service easier on the eyes of users, particularly in dark environments.
Here's all you need to know about WhatsApp dark mode and the way to enable it.
What the dark theme looks like?
As seen in beta builds, WhatsApp dark mode brings more of a dark grey-ish background with off-white text.
The effect, according to a company's spokesperson, has been specifically created to lower the brightness of a phone's display while cutting off high contrast, which was seen when they tested a pure black-and-white theme.
It could have even led to eye fatigue, the representative added.
This will make using WhatsApp easier than ever at night
WhatsApp says that the theme's lowered contrast, glare, and brightness will make it easier for you to chat in dark environments, rooms, et al.
The company also promises improved readability with the app, given that its color scheme has now changed.
To note, the theme finalized for iOS devices is darker than what's coming to Android.
So, how to enable the dark mode?
People using the latest version of WhatsApp on Android 10 and iOS 13 don't have to have to do anything to enable the dark mode.
The theme of the app, once updated, will automatically change according to system settings.
This means if you have dark mode enabled on a system level, WhatsApp will automatically go dark. If not, the light theme will stay on.
Enable manually on older operating systems
If you are using an older version of iOS or Android - which does not have a system-level dark mode, head over to the Settings of WhatsApp to enable the dark theme.
On the Settings page, go to Chats > Theme and select 'Dark' to get the theme working.
To go back to the light theme, head over to the same and select 'Light'.
Not seeing dark mode option?
The dark mode has just started rolling out and will become available for your phone in the next few days. So, if you can't see the update and the new 'Theme' option in the app then you might have to wait a little more.