Mark Zuckerberg has showcased the "Facebook phone" as he revealed the social networking site could now become the central feature on Android mobiles.
At a highly-anticipated event at the company's Menlo Park headquarters in California, he said consumers would be offered something far more than an "ordinary app" - an entirely "new experience" called Home.
He said: "We are not building a phone and we are not building an operating system, but we are are building something that is a whole lot deeper than an ordinary app."
Wearing one of his customary hooded jumpers, Mr Zuckerberg gave a relaxed presentation telling his audience: "We're really proud of Home and we're excited to get it in your hands ... we think that this is the best version of Facebook there is."
He was joined by Peter Chou, the chief executive of handset maker HTC, to reveal the companies' collaboration to produce HTC First - the only phone which will come with Facebook Home already installed.
In a short explanation of how Home would work, Mr Zuckerberg said: "The homescreen is really the soul of your phone. You look at it about a hundred times a day. It sets the tone for your whole experience and we think it should be deeply personal. So today we're going to talk about this new experience for your phone. It's a family of apps and you can install it and it becomes the home of your phone.''
In a short demonstration, Mr Zuckerberg showed viewers how the new product would appear on the homescreen of an Android phone and offered users the "highest quality experience''.
He added: "At one level, this is just the next mobile version of Facebook but at a deeper level, I think that this can start to be a change in the relationship that we have with how we use these computing devices. For more than 30 years computers have mostly just been about tasks and they had to be... but the modern computing device has a very different place in our lives.
"It's not just for productivity and business although it's great for that too. It's also for making us more connected, more social, more aware. And Home, by putting people first, and then apps, by flipping the order is one of many small but meaningful changes in our relationship with technology.''