After a spot of apparent confusion, Microsoft's Larry 'Major Nelson' Hryb has confirmed that the length of tonight's event revealing the next Xbox will be one hour.
In a tweet the Major stated:
This is in contrast to an earlier tweet from the official Xbox feed (as picked up
by NeoGAF) that stated the reveal would last around two hours. That tweet has since been deleted, so Hryb's information is looking more reliable.
The event starts at 6pm tonight.