Uber's CEO responds to the news that Apple invested $1 billion in its Chinese nemesis

It's difficult to know what Uber is thinking about the news that Apple is investing $1 billion (£693 million) into its Chinese archrival, Didi Chuxing.

The Californian ride-hailing app is yet to officially comment on the deal. But for now, Uber CEO Travis Kalanick is trying to make light of the situation.

Posting on Twitter, the libertarian exec wrote that his "girlfriend owns @Apple shares which makes her a didi investor … [shaking my head] #ridesharewars #domesticissues #thanksALotTim."

Oops.

(By the way, Kalanick is in a relationship with Gabi Holzwarth, a prominent violinist - pictured above.)

Uber and Didi Chuxing (formerly Didi Kuaidi) are locked in a battle for supremacy in China. The market - the largest in the world - holds huge potential with both companies raising vast billion-dollar-plus warchests in attempts to out-spend one-another.

Now Apple is lending a hand to Didi in a rare investment, funding it to the tune of $1 billion. The deal, announced on Thursday, was made "for a number of strategic reasons, including a chance to learn more about certain segments of the China market," Apple CEO Tim Cook told Reuters. Apple will also help Didi build its tech platform.

Apple is widely rumoured to be developing an electric car, potentially with self-driving capabilities. Didi Chuxing president Jean Liu told reporters on a conference call on Thursday that it is also an area of interest for the Chinese company: "We're big believers in autonomous driving and we believe technology is the solution ... We can work with different partners on autonomous driving, and it is technology neutral."

An Uber spokesperson confirmed the company is yet to officially comment on the Apple-Didi deal.