YouTube is the latest addition to the Now TV Box, with catch up services from all of the terrestrial channels – BBC iPlayer, ITV Player, 4oD and Demand 5 – already available through the device.
A new tile-based look has also been implemented on the Now TV Box homepage as part of efforts to make it easier to navigate through the available apps, which also include Facebook, TED Talks and Flickr.
Now TV director Gidon Katz said: "The Now TV Box offers a huge range of entertainment options to be enjoyed on your own big screen. The addition of YouTube means there’s even more to discover.
"With the flexibility to dip in and out of great movies, entertainment or sport with the relevant pass catch-up TV and now videos from your favourite YouTube channels, it’ll be hard to find an excuse to leave the sofa."
The news comes after it was confirmed that Now TV is now available on both the Xbox One and PS4.
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