NVIDIA announces details on how an update coming next month to their GeForce Experience software adding new sharing features as well as the ability to play co-op games over the internet with only a local copy on one machine. Here's word on how this works:

Last but not least is GameStream Co-op. As a kid you’d invite your friends around to see a new game, to help you beat a particularly tricky level, to play Chaos Engine co-op, or to challenge you in Doom II. As an adult, your childhood friends and new Internet friends are spread far and wide. GameStream Co-Op uses the Internet, the performance of GeForce GTX PCs, and the low-latency, low-overhead streaming components of GeForce GTX Kepler and Maxwell GPUs to solve the problem, enabling you to invite friends into your game over the Internet.

GameStream Co-op supports DirectX 9 games and up than run in fullscreen exclusive mode.

With GameStream Co-Op, your friends can simply watch you play in a low latency 1:1 stream, take control of your game with mirrored controls and help you with a tough boss fight in The Witcher 3, or play along-side you in supported multi-controller games like Trine 3, Gauntlet, FIFA 15, NBA 2K15, Mortal Kombat Komplete, and more.

However you use GameStream Co-Op, you’ll be able to hear your friend with built-in voice chat support, which can be activated and toggled in real-time using the new Share overlay.

To get your hands on all this goodness stay tuned to the GeForce Experience early access beta page, which will be updated with the download link in September. Further information regarding system requirements is already available, so you can see whether your system is ready for Share.