Mubadala, a United Arab Emirates state investment company, is investing $1.2 billion in Indian telco and digital services firm Jio Platforms.
The sovereign wealth fund, which has a venture arm split across Abu Dhabi and San Francisco, is the sixth investor to back Jio Platforms in as many weeks.
Other backers include Facebook, which is pumping $5.7 billion into the company in exchange for a 9.9% stake, and U.S. private equity firms Silverlake, Vista, General Atlantic and KKR.
Mubadala's stake in Jio Platforms, a company valued at $65 billion, will be almost 1.9%.
The Mubadala investment in Jio Platforms comes as the state investment vehicle stalls on whether to invest in SoftBank's Vision Fund II.
Jio Platforms has amassed over 388 million 4G subscribers on its Jio Infocomm mobile network since launching in 2016.
Today it is India's top telco and it also has several apps, and other services in e-commerce and broadband.
"Jio offers mobile Internet for nearly free and tries to make money by up-selling subscriptions to their own versions of Spotify and Netflix," said Vishal Gulati, a venture capital investor at London firm Draper Esprit.
Jio Platforms is owned by India's richest man, Mukesh Ambani, and it sits under his Reliance Industries business, which has a big focus on oil and petrochemicals.
Ambani is currently in the process of trying to sell 20% of Jio Platforms to raise money for Reliance Industries, which reportedly has a debt pile of around $20 billion.
The latest investment takes the total amount of capital invested in Jio Platforms to around $11 billion.
Home to 1.35 billion people, India is quickly catching up with more technologically-advanced nations and investors don't want to miss out on the opportunity that India presents.
In recent months, Silicon Valley has become increasingly interested in India. Google is reportedly considering taking a stake in Vodafone Idea, while Amazon is reportedly considering a stake in Bharti Airtel.