Steam have announced a spectator client allowing users to watch matches of Dota 2, complete with commentary.
The spectator client for Dota 2 allows you to watch current or recent matches for free with commentary, and every spectator feature available; including player perspective and directed view.
The spectator client also allows you to watch matches from the $1 million tournament, 'The International'.
Valve has said on the Dota 2 blog, that "this will become your full client once we expand server capacity enabling Matchmaking, Chat, Persona, etc."
Valve looks to be trying to gain more control over the eSports scene, particularly taking the lime light away from League of Legends.
To download the Dota 2 spectator client, you can do so through Steam.