Musk sent the following tweet at about 5.30pm UK time: “Major new Tesla product line - not a car - will be unveiled at our Hawthorne Design Studio on Thurs 8pm, April 30”. The result was thousands of retweets and favourites, as well as a $900 million lift in Tesla’s share price.

According to the Daily Telegraph, shares in Tesla, which is famous for producing high-end electric cars, jumped almost 4% in the 10 minutes following the tweet’s issue. It added $900 million to the firm’s market cap.

The hint that something big is about to be launched also sparked a frenzied hashtag discussion with #TeslaNewProductGuesses trending. According to the Telegraph, guesses ranged from a flux capacitor (the time machine from the film Back to the Future) to a real Iron Man suit, again from the movies.

Analysts speculate the announcement will be a home version of the vehicle battery Tesla uses in its cars. In February Musk alluded to the imminent launch of a “consumer battery”.

Major new Tesla product line -- not a car -- will be unveiled at our Hawthorne Design Studio on Thurs 8pm, April 30

— Elon Musk (@elonmusk) March 30, 2015

"We're going to unveil some of the Tesla home battery or consumer battery that will be for use in people's houses or businesses, fairly soon. We have the design done, and it should start going into production probably in about six months or so," he said.

Musk is widely seen as an entrepreneur in the Steve Jobs fold, with an ability to drum up interest in product launches with slick marketing and the clever release of teasers.

Other inventions produced by Musk’s businesses include rocket programme Space X and Hyperloop, a super-fast transportation system which fires train carriages along a cushion of air.

Musk says it could get people from Los Angeles to San Francisco (nearly 400 miles) in less than 30 minutes; currently by care it takes around six and a half hours.