Apple (NASDAQ:AAPL) and Chinese automaker BYD (OTCPK:BYDDF) worked secretly for years as part of the technology firm’s now-canceled car project, Bloomberg reported, citing people familiar with the situation.

For years, Apple was rumored to be working on a futuristic self-driving car, with the company tied to collaborations with Volkswagen and even a potential deal to buy McLaren at one point. That never happened and the project was canned after 10 years,

Apple Inc. worked with Chinese automaker BYD Co. for years as part of its now-canceled car project, developing long-range batteries that helped lay the groundwork for technology used today, according to people familiar with the situation.