The Lord Of The Rings Online is available to North American players now, with Turbine's Dungeons & Dragons Online to follow soon. Players can launch the full, free-to-play version of both titles from the games' official websites.
Gaikai EVP Robert Stevenson said: "MMOGs have always been one of the key genres we've wanted to deliver via the cloud – never before has it been possible to play MMOGs in this way.
"And we couldn't be more pleased to showcase Gaikai's technology by streaming Dungeons & Dragons Online and The Lord Of The Rings Online, which are both fantastic multiplayer gaming experiences with legions of loyal fans."
Craig Alexander of D&DO developer Turbine added: "Gaikai's game streaming service will make it easier than ever for new players to start their epic adventures in our immersive online worlds.
"Anyone wishing to try these popular MMOGs can now instantly launch the games inside their web browser, completely eliminating any download waiting time."
The deal currently only applies to North America. We've sought confirmation on if and when the games will be made available elsewhere, and will follow up when we hear back.