Elon Musk's Tesla is a growing player in China, where the global fight to develop electric, self-driving cars is raging hot.

Hong-Kong traded Tencent, a company best known for its WeChat messaging app, disclosed in a Tuesday filing that it's taken a 5 percent stake in Tesla for $1.78 billion. The investment follows Tencent's new stake in taxi-hailing app Didi Chuxing, which can be accessed through WeChat.

"I think Tencent likely wanted exposure to a company that was growing very quickly in electric and autonomous" vehicles, said Tasha Keeney, an analyst on the ARK Industrial Innovation ETF (ARKQ), whose top holding is Tesla.

"We think the autonomous mobility as a service market could be $10 trillion in gross sales globally by the early 2030s, and companies like Tesla or Baidu could take a cut of that," she said.

Tesla declined to comment to CNBC. Tencent did not respond to emailed requests for comment.

A Tencent spokesperson told The Wall Street Journal that "Tesla is a global pioneer at the forefront of new technologies. Tencent's success is partly due to our record of backing entrepreneurs with capital; Elon Musk is the archetype for entrepreneurship, combining vision, ambition, and execution."

Tesla has 24 stores in mainland China, 114 supercharging stations and 348 regular charging stations, according to the automaker's website.