For the first time, Showtime's content will be available via a TV Everywhere service now that it has joined Comcast's Xfinity TV stable of offerings.

Once Comcast's customers who already subscribe to Showtime authenticate themselves, they'll be able to view current Showtime episodes, as well as full seasons of shows, movies and sports programming, for free anywhere in the nation with a broadband connection.

Showtime's library includes original series, such as "Dexter" and "Weeds," as well as movies, including "Inglorious Bastards" and "The Reader," as well as sports programming that features Nascar, boxing and mixed martial arts shows.

As part of a special promotion, Comcast is giving all of its video customers access to the first season of "Dexter" online through Nov. 7.

With Showtime in hand, Comcast now has shows and movies from HBO, Cinemax, Starz, Encore and Movieplex.

The news of Showtime joining Comcast's TV Everywhere fold was blogged by Matt Strauss, senior vice president and general manager for Comcast Interactive Media. Strauss said in his blog that Comcast would have more Xfinity TV-related announcements in the coming months.

Earlier this week, Comcast announced the nationwide launch of Xfinity TV. Comcast's TV Everywhere service was rolled out in beta form in December.