Watch is aimed at allowing the social network to take on web rivals You tube as well as more traditional TV.
It will feature a wide range of programming, from live sports matches and safari expeditions, to a reality show about a day in the life of a social media star.
The redesigned video tab will initially be available to a limited group in the US but will be expanded to all users. Facebook launched its the Video tab in April last year and rumours have been flying that the Menlo Park firm was working on a new TV service.
It was reported in May that Facebook had signed deals with millennial-focused news and entertainment creators Vox Media, BuzzFeed, ATTN, Group Nine Media and others to produce shows, both scripted and unscripted. US users who are selected for the trial will be able to create 'watchlists', see what their friends are watching, and communicate with other people interested in the same videos.
There will be sections such as 'Most Talked About', which highlights shows that spark conversation, and 'What's Making People Laugh'.
Some of the shows will be funded by the social network, particularly if they are 'community-orientated'.
In a post on his own Facebook page, founder and chief executive Mark Zuckerberg said: 'Watching a show doesn't have to be passive. It can be a chance to share an experience and bring people together who care about the same things.
'That's why today we're launching the Watch tab in Facebook - a place where you can discover shows your friends are watching and follow your favorite shows and creators so you don't miss any episodes.
'You'll be able to chat and connect with people during an episode, and join groups with people who like the same shows afterwards to build community.'
Watch will be available on mobile, on desktop and laptop, and via the firm's TV apps.