A few weeks ago Sony sent out invites to select PlayStation 4 owners with an invitation to join a "small scale" closed alpha for From Software's Bloodborne and this initial test of the game is set to start tomorrow, as pointed out by AllGamesBeta.
At the time Sony commented, "The small-scale test is being conducted in order to gather community feedback and data to improve Bloodborne’s online experience.The Bloodborne Alpha Test is not final. Players may experience bugs and incomplete features that do not represent the final product. Thank you for helping us create a better experience for all fans when the game launches early 2015."
However, the test is very limited and access will only be possible between the following times: 18:00 – 21:00 (BST)/19:00 – 22:00 (CET) on Wednesday, Friday, and Saturday of this week.
In all, you'll have nine hours to play the game if you're part of the alpha. It's not a huge amount of time but it should give you a fairly comprehensive taste of what to expect and it's certainly longer than some entire campaign modes.
Bloodborne will be released in Japan on February 5th, 2015 and a day later in the West. Hopefully there will be more open tests of the game between now and then.