Electric car maker Tesla is getting ready to introduce two new...things.

The company is holding event on 9 October - at an airport of all places. It is expected to show off "the D and something else". Seriously. If you're curious about all the showmanship and mystery, keep reading.

Pocket-lint has rounded up the rumours and speculation, in an attempt to uncover what the D and that something else might be.

Tesla - technically referred to as Tesla Motors - is a US-based public company that makes and sells electric cars.

The car maker's first vehicle was the Tesla Roadster all-electric sports car, followed by the Model S sedan. Tesla in 2012 also unveiled another electric vehicle, called Tesla Model X, with plans to launch the crossover in small numbers by end of 2014. And finally, Tesla is developing a third-generation car, due out after Model X, called Model 3. It was originally codenamed Model E.

Elon Musk, the founder and CEO of Tesla Motors, said he had planned to name the next-generation electric car "Model E" so that Tesla's three car models - including the Model S sedan and Model X crossover - would spell out “SEX". Ford killed that idea however when it threatened to sue Tesla over the Model E trademark.

Musk tweeted on 1 October about Tesla's plans to announce new things on 9 October. The tweet included an image of a dark-coloured vehicle parked inside a shadowed garage, with the garage door showing the letter "D". Musk's tweet with the image stated: "About time to unveil the D and something else".

His followers of course translated the tweet into a sexual joke of sorts, which forced Musk to tweet the following just a few hours later: "I love the Internet. Comments had me literally ROFL. No, it wasn't intentional. Glad I didn't mention the other letter!"

Nevertheless, Musk teased that Tesla had two things to unveil. But he didn't say where.

Tesla Motors sent invites to a press event on 9 October near Los Angeles, presumably to unveil the D that Musk tweeted about the evening before. The event is being held at Hawthorne Airport. And so the question now is: what is Tesla unveiling and why is it using an airport as an event space?

While we can't yet speculate about why Tesla chose Hawthorne Airport, we can tell you what Tesla might show off. Keep reading to learn more.

The D is rumoured to be a new vehicle in Tesla's lineup.

The "D" could stand for a dual-motor, all-wheel-drive version of the Model S. The Verge spotted in a Tesla forum a picture of an unknown Tesla with the model tag “Model S P85D" (as seen below). Tesla already makes the P85 performance version of the Model S, so it is not far-fetched to think the D might be another upgrade.

The "D" could also stand for Driver Assistance. Tesla's recent software updates, as noted by Electrek's Seth Weintraub, have included land departure and speed assist features, which might signal that Tesla is embracing automation. That said, Musk told CNNMoney on 2 October that Tesla will unveil self-driving cars in 2015.

Google and other companies have been developing autonomous vehicle technology for years, but Musk claimed Tesla already developed a mostly-autonomous car. He said next year's Tesla car will likely be "90 per cent capable of autopilot... like so 90 percent of your miles can be on auto".

During the interview, Musk did not specify whether the self-driving Tesla car is the D or if it is the other mystery product he's planning to unveil.

Going back to self-driving cars for a moment, it is possible that Tesla could unveil a dual-motor AWD Model D as well as show off its early efforts at self-driving technology. The phrase "something else" presumably implies a less significant product or maybe even something that's not yet finished. Like an autonomous car.

Reports have also speculated Tesla could unveil something totally different, such as an electric motorcycle. The Street, for instance, quoted a senior analyst at Kelley Blue Book who predicted Tesla might unveil a truck or van at its 9 October event.

Keep in mind none of these rumours or predictions have been confirmed by Tesla. We just have to wait and see what the car maker does next.