The unaired fourth episode of the new season of HBO's hit series Game of Thrones has been leaked online, the premium channel's distribution partner Star India said on Friday.
The leak of the episode, titled The Spoils of War, was separate from a hack on HBO that was disclosed earlier this week, HBO said in a statement.
In that incident, the company's chairman, Richard Plepler, told employees in a Monday email that the hackers had stolen "proprietary information," including some programming.
Entertainment Weekly reported on Monday that hackers stole 1.5 terrabytes of data, including two unaired episodes of the Game of Thrones series.
"We take this breach very seriously and have immediately initiated forensic investigations at our and the technology partner's end to swiftly determine the cause," a Star India spokesperson said in a statement.
"This is a grave issue and we are taking appropriate legal remedial action."
Star India is a subsidiary of Twenty-First Century Fox Inc.
Game of Thrones has been hit by leaks in prior seasons and shared millions of times.