Tesla’s chief vehicle engineer has returned to Apple to work on the iPhone giant’s secretive self-driving car project.

Doug Field will join former colleagues at the Cupertino company where he held the role of vice president of Mac hardware, Apple has confirmed.

Tesla poached Field from Apple in 2013 stating that he had the “leadership and technical talent to develop and deliver outstanding products." Field was in charge of overseeing the Model 3 production line, which was plagued with operation glitches.

He left Tesla in May after taking “some time off to recharge and spend time with his family.” A month later, Tesla founder Elon Musk installed a makeshift assembly line tent outside the Tesla plant in a last ditch attempt to produce 5,000 Model 3 cars every week before the second quarter deadline.

Field will be involved in Apple's car division named “project Titan”, according to respected Apple Pundit John Gruber. Apple has declined to comment on whether Field is part of the car initiative or not.