Tesla boss Elon Musk has reiterated the company’s plans to develop an electric pick-up truck, and has hinted that it will include a “game-changing” feature.

Musk made the promise during an exchange with his Twitter followers, after asking them how the company could further improve its products. One user asked for an electric pickup, prompting Musk to reply: “I promise that we will make a pickup truck right after Model Y.”

The Model Y is a compact crossover based on the Model 3, and is set to go on sale in 2019 or 2020. The firm has already released images hinting at its design.

After the launch of the Model Y, Tesla had already announced plans for the pick-up, an electric cargo van and a minibus – all likely based on the platform of the Model X SUV. Tesla is also developing a new Roadster and a Semi truck.

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Developing the pick-up first makes sense, given the popularity of the vehicles in America. Ford sold 807,379 F-series trucks in the first 11 months of 2017, making it the best-selling vehicle in the USA, ahead of the Chevrolet Silverado and Ram Pickup trucks.

When asked about the Tesla pick-up’s size, Musk responded that it would be similar to the class-leading F-150. But then added: “Maybe slightly bigger to account for a really game-changing (I think) feature I’d like to add.” He did not offer any more specifics on the feature.

During his Twitter session, Musk also said that the infotainment browser in Tesla cars would be upgraded in 2018, admitting the current version was “terrible”. He added that the firm is aiming to put a major focus on sustainable energy production, but that Tesla’s “primary” focus would be on production of the Model 3 – the firm has fallen substantially behind in planned deliveries of the model in recent months.