Valve will release its Steam Controller in "October or November" this year, according a report.
Speaking to PC Gamer, a 'trusted hardware source' confirmed the information, adding that the controller's completion will lead the way to the availability of 'most' Steam Machines.
Meanwhile, the list of titles which will be natively playable on SteamOS has risen from 382 to 500, according to the same source.
Valve made significant changes to its Steam Controller in January, removing the central touchscreen and replacing them with standard face buttons. The company unveiled the first iteration in September 2013.
Valve confirmed 14 third-party Steam Machines in January from companies ranging Alienware to Origin.
Each will run Valve's Linux-based SteamOS, which promises "significant performance increases" over other operating systems.
The operating system is built especially for games designed natively for "living-room hardware", but users can also play existing Windows and Mac games on a television by running Steam on a home computer and streaming their games wirelessly over a home network.