You can watch "Game of Thrones" Sunday with only an Optimum Internet connection with the launch of HBO Now, the new streaming service now available on Apple TV and Optimum.

HBO Now costs $14.99 a month and does not require a cable subscription. It currently can only be streamed on Optimum or Apple TV streaming box, iPads and iPhones. It will not be available on Roku, Google's Chromecast or Microsoft XBox for another three months.

Although it appears to encourage "cord cutting" (people who pay for Internet but not cable), HBO CEO Richard Plepher told CNN's Brian Stelter that it is bringing in "millennial cord nevers," or people who are unlikely to ever have a cable subscription.

HBO had earlier said it would launch the service ahead of "Game of Thrones'" Sunday premiere, but had not given an exact date. Also on Tuesday, CBS launched CBS All Access on Roku for $5.99, a similar service that allows all CBS programs to be streamed with a cable subscription.

Note: amNewYork and Optimum are both owned by Cablevision.