The poaching of Chris Porritt, Tesla's former vice president of vehicle engineering, will no doubt annoy CEO Elon Musk, who once called Apple the "Tesla graveyard" due to the number of former employees who work there.
Steve Zadesky - a long-time Apple employee rumoured to be leading Project Titan - left the company in January this year, according to the Wall Street Journal. It's possible that Porritt will be taking his place.
Apple has never publicly spoken about its ambitions in the car industry, but a constant stream of leaks and rumours over the last year have all but confirmed the existence of the project.
Porritt's hiring is the latest in a string of tit-for-tat employee exchanges between Tesla and Apple, but given his seniority, this one could be fairly major.
Don't expect to hear anything about the Apple car soon - the company looks set to remain tight-lipped about it for the forseeable future, and even the most optimistic forecasts claim the car will only enter production in 2020.
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