HBO CEO Richard Plepler speaks at an Apple event in San Francisco. Reuters

HBO’s standalone streaming service HBO Now officially launched on Tuesday, enabling viewers to watch the channel's library of movies and original shows online without the need for a cable subscription -- just in time for the “Game of Thrones” season premiere.

But for the first three months, the benefit applies mainly to customers who own an Apple TV, iPhone, iPad or iPod Touch.

Like Netflix, HBO Now doesn’t require contracts or anything else beyond a 30-day free trial, followed by a $14.99 monthly subscription fee billed through iTunes. To sign up, Apple users can download the iOS app, subscribe and create a separate HBO Now account login, which can also be used to watch the service in a browser on Mac or PC. Apple TV customers can use the service through the HBO Now icon located on the home screen.

Apple has an exclusive deal to distribute HBO Now among tech companies. Time Warner Inc.-owned HBO is also launching HBO Now with Cablevision's Optimum Internet service in the New York City area. Cablevision is an existing distribution partner for HBO's cable service, so it has the right to also distribute HBO Now, which it decided to do for its broadband-only customers. HBO Now is one of many services that have emerged in recent months to cater to cord-cutters, or customers that have entirely ditched their cable TV subscription.