Moving the Tesla announcement to Wednesday. Needs a few more days of refinement.— Elon Musk (@elonmusk) October 16, 2016
The news sent Tesla shares 0.3 per cent lower to $196. But what is the product likely to be? Here's what the rumour mill says:
1. An energy storage device
Musk has promised to unveil new versions of Tesla's Powerwall and Powerpack at-home energy storage devices by the end of 2017. Given the company is in the throes of a $2.6bn (£2.1bn) buyout of green energy giant SolarCity - and has even gone so far as to announce a deal with Panasonic to manufacture solar panels for its Powerwall system - now could be the time for a reboot.
2. A new Autopilot
In a sense, Tesla is one of the earliest driverless cars to hit the road - although the path of its Autopilot feature hasn't run smoothly, after the technology was blamed for a fatal crash. To be fair, Musk has said repeatedly that the feature is designed to be used with drivers at the wheel and alert, but a new version of the technology would nonetheless be welcome.
3. An SUV
Admittedly, this is a little more off-the-wall, but in July Musk said Tesla wanted to cover "the major forms of terrestrial transport", starting from a sports utility vehicle (SUV) and moving on to trucks, buses and "high passenger-density urban transport". So is the Tesla SUV coming early? You'll have to wait until Wednesday to find out.
4. A shared fleet
Another revelation from Musk's strategy briefing in July was that Tesla wants to create a self-driving "shared fleet", meaning Tesla owners can rent out their self-driving cars, allowing them to "generate income for you while you're at work or on vacation". Has Musk already found a way to do it? Stranger things have happened.
5. Hyperloop II: TeslaSuperHyperloop
Musk is the man who came up with the so-crazy-it-might-just-work Hyperloop mass transportation system, essentially a vacuum tube which can carry passengers at 760mph (that's faster than a plane). If someone actually finds a way to make it, Hyperloop will cut the travel time from New York City to Washington DC to 30 minutes.
Has Musk come up with a new concept that could make travel even faster? Has he found a way to transport people at 760mph without inducing mass vomiting? We can but speculate. But while you're waiting, here's a video of Hyperloop in action.