Stardew Valley's developer, Eric Barone, has long promised a multiplayer mode for the popular farming/life sim. Chucklefish, the game's publisher, pushed back the release to the nebulous time period of "early 2018" stating that the multiplayer functionality needed more polish. On Sunday, Barone gave an update on the status of co-op, tweeting a screenshot of four people playing Stardew Valley.
When it does launch later this year, some features of the multiplayer addition have been confirmed. First, the update will not require players to create a new farm and existing saves will be open to co-op. Though the tweet references LAN gameplay, co-op will also be available via online play.
Given that the LAN connection is currently functional, we might reasonably expect to see Stardew Valley co-op sooner rather than later.