Electric carmaker Tesla Motors is expected to unveil an all-wheel-drive system at a highly-anticipated event Thursday night near Los Angeles.

Tesla won't confirm what it plans on showing before the event, to no surprise, but company CEO Elon Musk did offer a hint in the form of a tweet last week.

The tweet caused a swirl of speculation similar to that of a new smartphone not for a company that sells no more than 35,000 cars a year.

Telsa shares increased 4 percent the day after the tweet, according to the Associated Press. They were up 1 percent to $262.59 ahead of Thursday's announcement.

Musk plans to deliver the answer at the municipal airport in Hawthorne where another of his companies, SpaceX, is headquartered.

The company also has a design studio at the facility, according to the Associated Press.

A number of media outlets have speculated that the "D" is likely a reference to a "dual motor," all-wheel-drive system. Tesla's only vehicle, the Model S EV, is a rear-wheel drive, as one motor controls the wheels. This has hurt sales in snowy places like the Midwest, Northeast and in Europe.

Tesla sales were at 13,850 in the U.S. through September, which is down 3 percent from the same time in 2013.

"If Tesla wants to be seen a true competitor to brands like Audi, BMW, Jaguar and Mercedes-Benz, it needs to offer all-wheel drive," said Karl Brauer, a senior analyst at Kelley Blue Book, according to the AP.

Telsa has already promised that its upcoming new Model X crossover will have an all-wheel-drive system. It is expected to go on sale in the next year or so.

The company also recently upgraded its San Francisco Bay Area factory in order to manufacture the Model X, so it wouldn't be surprising if the system found its way into the Model S, which is also produced at the same facility.

Andrea James, an applied technologies analyst with Minneapolis-based Dougherty & Co., has heard all kinds of theories, like that the "D" could stand for "drop top."

She has doubts that a convertible is on the way though, believing that the "something else" could relate to "driver assist," according to the Associated Press.

Thursday's event is expected to be similar to the 2012 debut of the Model X in Hawthorne. Governor Jerry Brown, who attended the 2012 event, isn't scheduled to show up this time however.

Tesla also recently selected Nevada over California for its new $5 billion battery factory.

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