Google’s video calling mobile app Duo has a unique superpower! It lets Android users make calls to people in their contact list, even to those who don’t have the Duo app installed on their smartphones.

Fancy using Google Duo, but not many people from your contact list are using it? Well, that isn’t a problem anymore because Google’s video calling application is letting users make calls to those who don’t even have the app installed on their device. However, remember that this will work only for Android devices and it might also be possible that this feature may be available to just few users on your contact list, as of now; and the reason for this is unknown. Yes, we do know there is no official word on this feature from Google.

In fact, this feature was noticed by a Reddit user with name ‘turdbogis’ that a Nexus 6P unit, without the Google Duo app installed, was showing up as having Duo installed on another phone. The user also noticed in the list of Google Duo users that there was a sudden increase in the list of contacts who have installed the app, which means the feature on Duo would be relatively new. Some who tested this feature also noticed that this feature works on audio-only calls too and recipients without the app can do stuff like answer/hangup the call, mute it, and switch cameras like any other normal Duo user.

What’s more, the receiving side of Duo works exactly like a normal Duo call, including the Knock-Knock feature that lets you see the preview of the caller before you pick it up. There’s even a persistent notification icon that allows you to switch to another app and back again, while it is still connected. Oh, and they can also block a caller from contacting them again, without the app! This is all new, right? But yes, the one time anyone will need Duo installed is when they want to make call and become the caller.