If you've been looking forward to The Witcher 3's card game finally breaking off into its own thing, good news!
CD Projekt RED announced on their website that invites have gone out to those who registered for the closed beta, which you can still do here.
"We plan on sending out more codes in future waves," one of the developers wrote. The closed beta is available for PC and Xbox One only, although Gwent is coming out for PS4 at a later stage. The beta won't have a single player mode, although the FAQ says they are planning to add single-player adventures (probably not too dissimilar from those in Hearthstone) "as time passes".
And if you don't get into the beta in the first few waves, don't worry. The closed beta will run until autumn next year, although CDR says "that's only a rough estimate".