Apple CEO Tim Cook has finally confirmed that Apple is working on self-driving car technology.

Apple's work in the automotive space has been a closely guarded secret for many years. But Cook told Bloomberg earlier this month that Apple has been quietly working on self-driving cars behind closed doors. The interview was published on June 13.

"We're focusing on autonomous systems," Cook said in an interview at Apple's WWDC conference on June 5. "It's a core technology that we view as very important."

Cook added: "We sort of see it as the mother of all AI [artificial intelligence] projects. It's probably one of the most difficult AI projects actually to work on."

Apple has never admitted that it is working on car technology before now, but the company has recruited dozens of automotive experts from companies like Ford and Mercedes-Benz, according to The Financial Times. It has more than 1,000 engineers working on automotive, according to Bloomberg.

Apple's self-driving car efforts are known internally as "Project Titan." They have been the subject of rumours and speculation for years.

It was initially thought that Apple was working on its own car but Apple's focus is now believed to be on building autonomous software instead.

Documents obtained by Business Insider in April gave us a first look at some of Apple's self-driving car technology. The documents showed that Apple has developed a system "capable of sending electronic commands for steering, accelerating, and decelerating." They also highlighted how Apple is planning to put staffers through a training program to operate the vehicles ahead of testing on California roads.

Silicon Valley heavyweights like Google and Uber are carrying out their own research into autonomous cars, as are many of the traditional car manufacturers, including BMW, Daimler, and Volkswagen.

Here's everything Cook said in the Bloomberg interview:

"I think there is a major disruption looming there. Not only for self-driving cars, but also the electrification piece.

If you've driven an electric car, it's actually a marvellous experience. It's also a marvellous experience to stop at the filling station, gas station, whatever you want to call it. Plus you have ridesharing on top of this. So you’ve got three vectors of change happening generally in the same time frame.

As we look at it, what we're focusing on, what we've talked about focusing on publicly, is we're focusing on autonomous systems. Clearly one purpose of autonomous systems is self driving cars. There are others. We sort of see it as the mother of all AI projects. It's probably one of the most difficult AI projects actually to work on. So autonomy is something that’s incredibly exciting for us, we’ll see where it takes us. We're not really saying from a product point of view what we will do but we are being straight forward that it's a core technology that we view as very important."