Amazon.com Inc. has joined Tencent Holdings Ltd. and the main assembler of iPhones in backing Essential Products Inc., the startup co-founded by Android-creator Andy Rubin that’s getting ready to sell a new smartphone.

China’s largest social media company and Foxconn Technology Group took part in a $300 million funding round for Essential alongside Amazon’s Alexa Fund and Access Technology Ventures, the VC firm said in a statement. Other backers included Redpoint Ventures, Altimeter Capital and Vy Capital. Access said it contributed about $100 million to the pot