This is seven times as much data as was stolen from Sony in the 2014 hack, which involved roughly 200 gigabytes of data.
The FBI has been reportedly called in to investigate the HBO hack that saw spoilers for Game of Thrones and complete unseen episodes of other shows released in a massive data breach.
According to the Hollywood Reporter, the incident is being investigated by the FBI as well as cyber security firm Mandiant, which was involved in investigating the Sony hack.
The hackers have apparently already leaked what appears to be the personal data of at least one senior HBO executive, including details of her finance and health plan.