Within the next hour Nintendo will reveal the console that is currently codenamed Nintendo NX. The console will be revealed via a "preview trailer" that will be livestreamed live.
It is unknown what the preview trailer will show though it is likely that it will reveal what the console looks like and how it will work. The trailer could also show gameplay of several launch titles.
The trailer will be released at 7AM PT / 10 AM ET / 2PM GMT / 3PM BST.
Update: Nintendo has just announced Nintendo Switch.