Tesla Inc Chief Executive Officer Elon Musk just gained a massive and well-connected confidant to help him gain better access to China's auto market: Tencent Holdings Ltd.

The Chinese internet giant isn't just an investor, Musk said after his electric-car maker disclosed Tencent had bought a 5 percent stake in his company for $1.8 billion. He also referred to the owner of the WeChat and QQ messaging services as an adviser.

"Tencent's passive stake is not only a vote of confidence in Elon Musk and the future of EVs, but also may help in accessing the Chinese market," Brian Johnson, an auto analyst at Barclays Plc, wrote in a note to clients Tuesday.

Tesla stumbled out of the gate in China, with Musk blaming his sales staff for underwhelming results and stoking fears about charging challenges soon after deliveries began in 2014.

While the company has been getting better traction - revenue from China tripled last year to more than $1 billion - sales from the market were still less than a quarter of what Tesla made in the US.

Tencent's purchase vaults the company to the position of Tesla's fifth-largest shareholder just as Musk prepares to start production of his mass-market Model 3 later this year, and as Tesla scouts for additional "gigafactories" that would further boost battery production.

Tencent is adding to existing investments in technologies that are reshaping the auto industry and the future of mobility, including ride-hailing apps and the maps and artificial intelligence needed for driverless cars.

"Having Tencent as a partner helps position Tesla to launch the Model 3 in China," said Joseph Fath, a fund manager at T. Rowe Price, Tesla's fourth-largest shareholder, in a phone interview. "Tencent is one of the three superpowers in China along with Baidu and Alibaba, and they clearly have a lot of backing from the government."

Tencent purchased Tesla shares on the open market and from Tesla's stock offering earlier this month, according to a regulatory filing.

Tencent Chairman Ma Huateng said earlier this month he envisions Tencent developing AI technology for driverless cars in the future. The Shenzhen-based company is one of the biggest investors in Chinese ride-sharing giant Didi Chuxing and owns stakes in mapmakers NavInfo Co. and HERE, the German consortium owned by BMW AG, Audi AG and Daimler AG.

Tencent also is adding to existing bets on electric cars. It was an early backer of Nio, the startup owned by Chinese internet entrepreneur William Li and originally called NextEV Inc. Nio's US headquarters are in San Jose, California and the company has vowed to bring a plug-in autonomous car to the US market by 2020.

There are no detailed plans for cooperation with Tesla at the moment, according to an emailed statement.

"Elon Musk is the archetype for entrepreneurship, combining vision, ambition and execution," Tencent said in the email. "Tesla is a global pioneer at the forefront of new technologies including electric vehicles, assisted driving, shared vehicles, digitizing real-world information, sustainable energy generation and scalable energy storage."