The doorbell - aptly named Hello - is able to detect when a person is standing in front of it and will take a snapshot of that person before they even have a chance to ring the doorbell. From here, using Nest Aware, it can send a message to the owner if they detect something unusual happening.
Nest Hello also allows its users to speak with the person at their front door from anywhere, using the HD Talk and Listen function. It comes equipped with echo suppression and ambient noise cancellation, which ensures a clear line to hear the person.
There is also a list of pre-recorded responses that can be used to answer visitors with a single tap on the app.
During their big unveiling, Nest also revealed a number of other home security products including alarm system Nest Secure and a smart camera, the Nest Cam IQ Outdoor.
Marwan Fawaz, chief executive officer of Nest, said: "Today, Nest is delivering on the next phase of our strategy to create the thoughtful home. We've had quite a year so far, expanding into 11 more countries, growing our product portfolio with the successful launches of Nest Cam IQ indoor and the Nest Thermostat E, and today we're disrupting yet another product industry: home security. By building product experiences our customers love, Nest has experienced more than 60% growth on devices shipped in recent years and continues to expand to millions of homes around the world."
Nest's Hello Doorbell will be available in early 2018.