The Google-owned website has given itself "a fresh coat of digital paint" in a redesign of the service that attracts more than three billion video views every day.
Following an announcement in October that over 100 original channels are coming to YouTube, the revamp is primarily focused on making this new material more accessible to users.
The new homepage is intended to be a "gateway to a vast entertainment universe", including a bar on the left side featuring options to personalise YouTube, adding links to videos shared by your Google+ and Facebook friends.
The navigation bar also lists all the channels to which you are subscribed, along with the topics that are trending worldwide at that moment.
Accessing a channel or video flagged on the social networks shifts the clip to the middle section, which is intended to be Facebook-esque newsfeed featuring recent activity.
The video feed, announced earlier in the year, will auto-populate with videos from subscribed channels and social networking friends in default mode.
On the right hand side, a column features recommended content related to users' recent YouTube video viewing history.
YouTube said in a blog post: "Our recent Channels expansion, our grants and educational programs, and this new design are all focused on helping you discover a broader range of entertainment on YouTube.
"We're always innovating and testing new stuff out to make the experience the best it can be for you. We rely on your feedback to figure out when we've gotten it right and when it needs further tweaks. So let us know what you think."
Watch a video explaining YouTube's new look below: