Disney already has a booming streaming service. It's called Hotstar

New Delhi (CNN Business) Disney is taking on Netflix with a new streaming service in the United States. But there's an even bigger and hotter market where it's already winning by miles — India.

Hotstar, which Disney bought from 21st Century Fox last year, already has nearly as many users as the entire US population. And it's growing incredibly fast.

The Indian platform now has 300 million monthly active users, Disney (DIS) revealed during its investor day on Thursday. That means its user base has quadrupled in a little over a year — Hotstar had around 75 million monthly active users in India at the end of 2017.

"India has emerged as a thriving market," said Uday Shankar, president of Disney's Asia Pacific unit.

And there's plenty more growth for Disney to target.

India has over 500 million internet users, more than any country except China. But there are more than 800 million Indians that have yet to be connected. Companies are racing to reach them.

Global streaming services like Netflix (NFLX) and Amazon Prime Video (AMZN) are making a big push in India, commissioning dozens of original movies and TV shows. Netflix CEO Reed Hastings predicted last year that the platform's "next 100 million" users would come from India.

Disney is already way out in front thanks to Hotstar. At the end of 2017, the Indian platform dwarfed Amazon and Netflix, which had 11 million and 5 million Indian users respectively, according to Counterpoint Research.

Neither of Disney's rivals share country-specific user data, but Netflix has around 150 million subscribers globally.

India has become "a magnet" for content companies, Shankar said Thursday. Hotstar has no intention of giving up its dominant position without a fight.

The platform has content in eight Indian languages and owns the broadcast rights to the hugely popular Indian Premier League cricket tournament. It also owns the Indian rights for HBO's hit TV show "Game of Thrones."

India already has about 550 million video screens, 63% of which are smartphones and the rest televisions, according to data cited by Disney on Thursday.

Hotstar is aiming much higher than that. "Inspire a billion imaginations," reads its tagline.