A Steam Community Group Announcements informs owners of Don't Starve on Steam who bought the game before today have received a free copy of Don't Starve Together, the game's standalone multiplayer expansion (thanks PCGamesN). Here's word:

Today, we welcome 2 million new players into the Don't Starve Together community. Thank you once again to everyone who supported us on this journey. For everyone who purchased Don’t Starve, to everyone who jumped into the Frontier Pack, to everyone who told their friends about our little game -- thank you!

Over the last 6+ months, we’ve been updating the game[forums.kleientertainment.com] at a furious pace[forums.kleientertainment.com], and all the while, we’ve been upgrading our backend to get ready for bigger load. Since our Early Access launch in December, we’ve added new creatures, integrated the Reign of Giants DLC for free, created new games modes, added significant improvements to modding, and in general made over 50 significant updates to the game. While we’re not yet done (see below!) we feel players have waited long enough.

And on the note of new updates, today we are releasing an update to Willow. Full update notes will be available later today, but suffice it to say that she has been reunited with an old friend.