Looks like multiplayer and maybe singleplayer, too
It didn't take any sort of elite level hacking skills or espionage database infiltration, just a keen eye to find out that Watch Dogs appears set to have a closed beta on Xbox One before its May 27 release. A listing for the The beta showed up prematurely on the console's marketplace.
The observant player posted an image of the closed beta to reddit. The download clocks in at more than 23GB, and supports up to eight players, suggesting that it's the multiplayer component that will be tested. However, a singleplayer option's also mentioned.
It's currently unknown how the beta can be registered for, or what date it might launch. Additionally, the listing has since been pulled from the digital store. Regardless, it looks like some may get to visit The Windy City a tad early.
Just found this on the store! [reddit]