Two of the top pay cable outlets are joining Comcast cable to offer customers streaming versions of their shows and movies according to the Hollywood Reporter.

HBO and Cinemax are joining basic cable outlets TNT, TBS and the pay outlet Starz in offering streaming episodes of their popular shows.

Comcast announced Monday it will be streaming HBO and Cinemax shows, movies and other content online to 5,000 subscriber households in a national trial set to start in coming weeks. It is the first time the two premium movie channels will be offering their programs over the Internet to computers. Downloads to mobile devices may come in the future.

The trial is part of a joint effort with Time Warner Inc. to offer cable programming on the Internet as viewership increasingly moves outside of the living room. But programmers and pay-TV operators will provide access only behind a walled garden of subscribers.

Unveiled last month, the venture dubbed “TV Everywhere” by Time Warner and “On Demand Online” by Comcast began with TNT and TBS.

The cable channels will be available through Comcast.net and Fancast.com, Comcast’s video aggregator site supported by advertising. About 750 hours of programming a month initially will be available and expected to increase over time.

Critical to the trial is authentication of viewer as a paying subscriber. Users will be asked to log on with a user name and password. If they are paying for the five cable networks, the system will authenticate them.

The trial includes only Comcast customers of both video and Internet services. In the future, deals will be made with other ISPs, even Comcast rivals such as phone companies.

The HBO and Cinemax trial will include full-length episodes of “Entourage” and “Curb Your Enthusiasm” as well as movies including “Kung Fu Panda” and “The Dark Knight.”