Facebook has unveiled 'Home', a suite of apps designed to turn your phone into a device about apps and into a device "about people".
"All of the interactions are really smooth and natural," Zuckerberg said, adding that Facebook "wanted it to feel like system software rather than an app."
"With Home," Zuckerberg said, "You see your world through people, not apps."
We have all the details elsewhere, including what phones will work with the new apps - and when you can get your hands on them.
But if you just want to get the basics about how it looks, and how it works, we have you covered to.
Below we've pulled together the best pictures of the new 'OS Lite'.
Take a look and let us know what you think in the comments.