You'll most likely need an HTC Vive to make this work (there's no mention of supporting other SteamVR devices yet), and Valve hasn't said when the feature will arrive. Suffice it to say, though, that this could be the best way to watch DOTA competitions short of flying out to see an event in person -- it might even be more entertaining than playing the game yourself, at least until the novelty wears off.

Footage of VR spectator mode for #dota2 with @htcvive. Things could NOT get any more exciting today. pic.twitter.com/3f4sEfUX8U — Robert McGregor (@ID_R_McGregor) April 5, 2016