Once the new feature is set up, users are able to select a speaker in a specific room and communicate with it one-to-one - to call the kids to dinner from the kitchen Echo, for example.
To enable the function, users must first give a distinctive name (such as a room) to each Echo in their household and enable the Drop-In feature using the Alexa app.
The intercom system works through household groups created during the setup process, meaning it's not limited to speakers on the same Wi-Fi, so it's possible to communicate with Echo-owning friends or relatives in a different area code, for instance. Users can also use the feature away from home using the Alexa app.
The Drop-In feature first appeared on Amazon's new Echo Show with integrated display, with some reviewers finding the video aspect a little intrusive. Similarly, there doesn't seem to be a way to block the intercom audio on the standard Echo range, so it's worth keeping this in mind before enabling it.
The update is rolling out to the Echo family of speakers this week.