Tesla Motors will unveil its first affordable, mass-market electric vehicle in California on 31 March, but the automaker doesn't plan to reveal everything all at once, according to a recent tweet from Elon Musk.

Musk, the co-founder, CEO, and "product architect" of Tesla Motors, has said on Twitter the Tesla Model 3 event will technically be "part one" of a two-part launch, with the initial unveiling slated to occur during the actual event. The "part two" aspect, which hasn't been clearly defined yet by Musk, will apparently take things to another level closer to production. The car is expected to go on sale in limited numbers in 2017.

In a follow-up tweet, Musk clarified to the world that we should see the Model 3 "very clearly" during the event and that "some important elements will be added and some will evolve." We therefore get the feeling Tesla is warning consumers not to expect much from the Model 3 event. It seems like some ground-breaking features of the car aren't ready to be unveiled, but they're still in the works and coming down the pipeline.

The Model 3 is thought to be a critical, perhaps make-or-break product for Tesla. The company's first electric car was a small-scale Roadster, followed by the Model S saloon and Model X SUV. None of the vehicles are cheap, which explains why Tesla only sells around 50,000 cars per year and loses money despite its overwhelming critical success. Delivering an affordable car for consumers could change all that however.

Musk has confirmed Tesla will unveil the Model 3 during its 31 March event.

The Model 3 is thought to be a four-door sedan. Musk has already shared some key attributes of the car, like its 200-mile range and $35,000 price tag. Other than that, there have so far been relatively few leaks of any details. The biggest mystery surrounding the Model 3 is what it’s going to look like. Musk has only said the Model 3 "won’t look like other cars.”

Apart from the Model 3, there may even be another vehicle announced at the event. Called the Model Y, it's rumoured to be a crossover variant of the Model 3. Check out this round-up for more information about both cars:

The event will stream live on Tesla.com at 11:30 pm EST/ 8:30 pm PST.

Pre-orders for the Model 3 will begin during the event on March 31 in Tesla stores only and will require a $1,000 reservation fee. You can check this page to find a dealership in your area. Alternatively, you can wait until 1 April, when online reservations open up worldwide.

Stay tuned to Pocket-lint's Tesla hub for related news and analysis.