Uber's CEO had a meeting planned with Apple this week - then Apple invested $1 billion in Uber's main rival

Uber CEO Travis Kalanick was planning a meeting at Apple's headquarters this week, The Information reports.

And now that meeting might be a whole lot more interesting, since Apple made a surprise announcement on Thursday that it's investing $1 billion in Didi Chuxing, Uber's main rival for ride-hailing dominance in China. It's unclear whether the meeting is still scheduled. 

As the report notes, Apple and Uber already work together closely. 

Apple has tapped Uber to be a prime partner for new App Store and device launches. For example, when Apple launched the Apple Watch in April 2015, Uber was one of the first app demos revealed by Apple's Kevin Lynch.

Uber also buys a lot of iPhones to equip its drivers. 

Didi Chuxing is the top ride-hailing app in China, and has been leading a worldwide alliance between Uber rivals. Soon, for example, the Lyft app will be able to book cars from Didi Chuxing's service in China. Those companies, including Ola and GrabTaxi, are sharing technology, market knowledge, and resources.

Currently, Didi users visiting the United States can use the Didi app to hail a Lyft car.  

"Didi exemplifies the innovation taking place in the iOS developer community in China. We are extremely impressed by the business they've built and their excellent leadership team, and we look forward to supporting them as they grow," Apple CEO Tim Cook said in a statement. 

Neither Apple nor Didi has commented on Didi Chuxing's post-investment valuation. Previous reports indicated it was raising at a $25 billion valuation. 

Earlier this month, Cook and Uber CEO Travis Kalanick were spotted together at the Met Gala. The two appear to be on friendly terms, and after the news broke, Kalanick didn't seem to be too stressed, cracking a joke on Twitter: