HTC decided on telepresence for the unveiling of the new HTC 10 instead of an in-person presentation. The stream starts 1 pm London time, 8 am New York time and 8 pm Taipei time.
We'll embed the stream here when it starts available so that it's easier to find.
Update: no livestream it seems, but here's a 12 minute announcment video.
By the way, several hours after the event is over, HTC will let us play with the 10 unit so we'll have first-hand impressions of the device later on.