Update: Clarified Carmack's involvement with the Rift prototype unit itself, thanks Candiedbug!
id Software co-founder and lead programmer of the classic Doom and Quake series John Carmack earlier today confirmed he has adopted the mantle of Chief Technology Officer for Oculus VR, the team behind the curious Oculus Rift virtual reality HMD (head-mounted display).
To be sure, Carmack has been involved with Oculus Rift development since its very inception; he in fact helped introduce the prototype (developed by Oculus founder Palmer Luckey) seen back at E3 2012 before fundraising began in earnest.
Bethesda (which like id Software is owned by ZeniMax Media) notes to Gamasutra that the "technical leadership [Carmack] provides for games in development at id Software is unaffected" as a result of his new post at Oculus VR. Carmack himself tweeted that he'll now be dividing his time between id, Oculus, and Armadillo Aerospace.