Looks like the rumors are true, folks! Nintendo of America, Europe, and Japan have confirmed that a Nintendo Direct will be broadcast live on September 13/14, 2017 (depending on where you live).
The Nintendo Direct will be covering new titles that are heading to Nintendo Switch and Nintendo 3DS in the coming months and Super Mario Odyssey. It will last for 45 minutes in Europe, and 50 minutes in Japan.
Here are the times for the Nintendo Direct in various regions:
United States: September 13, 2017 15:00 (PT)
United Kingdom: September 13, 2017 23:00
Europe: September 14, 2017 00:00 (CEST)
Singapore: September 14, 2017 06:00
Japan: September 14, 2017 07:00 (JST)
You can watch the Nintendo Direct here.