HBO's medieval fantasy drama "Game of Thrones" has gained a cult-like following since first airing four years ago, and now the network is paying a price for that popularity.
"Game of Thrones" is already the most pirated television show in 2015, research shows, as new episodes were leaked over the weekend ahead of Sunday's official fifth season debut.
Episodes from the first four seasons of "Game of Thrones" were downloaded over 7 million times worldwide from February 5 through April 6 this year, anti-piracy firm Irdeto said on Friday - a 45 percent increase from 2014.
Irdeto's findings come as the first four episodes from the show's new season emerged on BitTorrent sites Saturday. Within a 24-hour period, the episodes were downloaded well over a million times worldwide, according to several media reports. The leak deals a blow to HBO's plan to simultaneously broadcast the first episode across 170 countries on Sunday evening Eastern time.
In a statement, HBO said the leaked episodes originated from a group approved to receive them, adding that it's actively assessing how the breach occurred.
In the past, Time Warner, the owner of the HBO network, hasn't expressed worry about piracy. Last year, CEO Jeff Bewkes was quoted as saying the show's skyrocketing downloads were "better than an Emmy." Despite its negative impact on a cable company's bottom line, piracy can be interpreted as a positive factor in terms of high audience engagement.
But as downloads continue to spike, Irdeto said that companies are becoming more concerned.
"It's often said that piracy is good marketing, but the mindset is shifting toward offering a compelling legal alternative like HBO Now to start converting pirates into paying customers," said Rory O'Connor, vice president, services, at Irdeto.
HBO Now is a new streaming service targeted for consumers without a cable subscription. Joining the ranks of Netflix and Hulu, the product is an expansion of HBO's cable business, CEO Richard Plepler told CNBC last month.
Hollywood recently upped its battle against online piracy. Earlier this month, a U.S. Federal Court ordered Australian internet service companies to provide names of users who illegally downloaded the film Dallas Buyers Club.
Developing countries like Brazil and India are increasingly contributing to the rise in piracy, Irdeto noted, as broadband penetration improves.
The second most pirated show of 2015 was "The Walking Dead" with 5.7 million downloads during the February 5 - April 6 period, followed by "Breaking Bad" (3.8 million), "Vikings" (3.4 million) and "House of Cards" (2.7 million).