Sony has announced that the Uncharted 4 multiplayer beta will go live tomorrow, December 3rd, at 9am PT/12pm ET/5pm UK. The beta was previously due to start on the 4th of December.
The beta will allow players to particiapte in 5v5 team deathmatches across two different maps. If we go by what Naughty Dog did in previous betas for other games, it might be possible that we get more content, possibly new maps, midway through the beta. Unfortunatelly, any progress made during the beta won't carry over to the full game.
In terms of space, the Uncharted 4 beta will take approximately 7GB, but Naughty Dog warns that the size could be a bit bigger in some countries due to language options. Access to it is exclusive to those that purchased Uncharted: The Nathan Drake Collection.
Uncharted 4: A Thief's End releases on the 18th of March on PS4.
Source: Twitter PlayStation Europe