Linux support was confirmed by Chris Roberts at PAX East. The session where he announced it and made other interesting game comments was during the future of PC gaming panel, with the relevant segment being embedded below from the video stream (at 21 minutes 50 seconds, if the clip doesn't auto-start there).
Star Citizen is a space tracing and combat simulator game coming out that's powered by a modified CryENGINE. The Linux engine port of Crytek's flagship game engine was announced last month during GDC 2014. Star Citizen was initially funded in 2012 via crowd-funding and through its ongoing crowd funding has rose past $42 million USD. Star Citizen is made up of a first person space combat and trading within a massively multiplayer persistent universe and there's also a branching single-player and drop-in cooperative multiplayer campaign mode.
More details on the game can be found via the Star Citizen web-site. Look for this high-quality space game to launch in 2015.