At it's #XboxE3 briefing in LA, Microsoft just opened up with a bang by announcing backwards compatibility for Xbox One so you can now play all your Xbox 360 games on the new console!

Digital titles already purchased will just appear in your library on the Xbox One, but better still all your disks amassed over the years can also be used.

Microsoft demonstrated Mass Effect from the Xbox 360 running on the Xbox One where it ""runs exactly as on the 360, but better."

The feature will become available to all during the holiday season, but Xbox Preview members will get to try it out starting from today. Multiplayer support is included as are Xbox One specifics such as taking screenshots and broadcasting. Initially there will be 100 titles ready to roll with hundreds more coming soon after.

It requires no work from developers but it does require their permission. But apart from that it's what many Xbox One owners have been waiting for since, well, pretty much day one!

Join us in our #XboxE3 liveblog for much more live from LA!