Google has become the latest US technology giant to invest in Indian conglomerate Reliance Industries' digital business.
The Alphabet-owned search engine has agreed to pay $4.5bn (£3.6bn) for a 7.7% stake in Jio Platforms.
Reliance's billionaire owner Mukesh Ambani says the two companies will develop phones for 4G and 5G networks.
Google joins a list of new investors in Jio that includes Facebook, Intel and Qualcomm.
"Google has empowered millions of Indians to access helpful information and, like Jio, is a force for change and innovation," Mr Ambani said in a statement to shareholders.
Google's chief executive Sundar Pichai said: "The pace and scale of digital transformation in India is hugely inspiring for us and reinforces our view that building products for India first helps us build better products for users everywhere."
Earlier this week Google also said the company would invest about $10bn in India over the next five to seven years.
In April Facebook said it would invest $5.7bn for a 9.99% stake in Jio, making it the cut-price Indian mobile internet provider's largest minority shareholder.
The investment arms of US technology giants Intel and Qualcomm have also bought smaller smaller stakes in the company.
Arunoday Mukharji, BBC News, Delhi
Mr Ambani has been on a shopping spree, managing to hook 11 big investors in the last three months and raising over $20bn.
Not only has it helped him remove his net debt of $21bn, he is now looking to expand in the e-commerce space to rival giants like Amazon in India.
His online venture Jio Mart wants to tap into Facebook-owned Whatsapp's 400 million users in India to connect customers with their nearest mom and pop stores - hugely popular in India.
This is why the $6bn Facebook investment in April becomes even more significant.
Mr Ambani also said his company had developed a fully home-grown 5G network. This is important for two major reasons.
First, it fits the script of Prime Minister Modi's repeated push for a self-reliant India.
Second, and more importantly, it seriously damages prospects of tech giants like China's Huawei, which was looking to participate in India's 5G trials.
In the aftermath of the recent border standoff between India and China, the government has been reconsidering all major business engagements with China.
Jio, which is India's newest major mobile operator, grew rapidly to take the number one spot late last year.
Since launching in September 2016 the low cost service has attracted almost 400m subscribers and aims to increase that figure to 500m in the next three years.
In January Reliance announced that it would launch a grocery delivery service that aimed to compete with Amazon in India.
US technology companies see India as a key market for growth, with the number of internet users there seen rising to more than 850m in 2022, according to consultancy firm PwC.
Mr Ambani, who is the chairman and managing director of Jio's parent company Reliance Industries, is now the world's ninth-richest person, with a net worth of $68.7bn, according to Forbes.