MTV’s “Teen Mom,” “Teen Wolf” and other youth-skewing TV fare are now playing on mobile devices — but fans will get full access only if they’re lucky enough to have a pay TV provider currently on board with Viacom’s TV Everywhere program.

The new MTV app for Apple’s iPad and iPhone, skedded for Thursday release, will include access to current-season shows and older titles (“iconic retro” were cabler’s words) like “Beavis and Butt-head,” “Daria” and “The Real World.”

“You’ll see it focusing much more on our current franchises,” said Kristin Frank, exec VP of connected content for Viacom Music and Logo Group.

The “three-in-one” MTV app offers full-length TV episodes, short-form digital content and a second-screen Connect feature that displays Twitter comments, provides live discussions and synchronizes content (such as trivia, video and photos) with on-air programming. “The goal is to get fans to use these apps on a daily basis,” Frank said.

Viacom execs acknowledged that users have been clamoring for mobile video from MTV — and that the launch of the video-centric app was delayed. Frank said incorporating social and second-screen features into the app, rather than just going out with one for TV Everywhere, pushed back the sked. In addition, “We also wanted to wait until we had a critical mass of distributors” for authentication.

The programmer plans to launch a similar branded app for VH1 later this summer, followed by versions for CMT and Logo. Earlier this year Viacom’s Nickelodeon kidvid channel introduced apps for iPhone and iPad, which also provide TV Everywhere video and other digital content.

While the industry’s TV Everywhere concept is now more than four years old, authenticated services overall have been stymied by low awareness and a patchwork quilt of content from networks, available via a subset of pay TV partners on varying devices.

In Viacom’s  case, “critical mass” currently means about half the pay TV universe, with two of the biggest providers — Comcast and Dish Network — not signed on for Viacom’s TV Everywhere. Full-length episodes will be available to subs with one of nine distributors, representing close to 50 million households: DirecTV, Time Warner Cable, Verizon FiOS, AT&T U-verse, Cablevision, Bright House Networks, Suddenlink, RCN and Hawaiian Telecom.

There’s still a bunch of material in the app for those stuck in TV-nowhere land. All users of the app are free to access at least one episode from each current series plus all the original short-form video, including MTV Other, a new section stocked with shows from Viacom’s experimental content lab featuring young and emerging talent. The new app subsumes MTV’s previous second-screen app, WatchWith, which has been downloaded nearly 1.5 million times.

Launch sponsor of MTV’s app is PepsiCo, which also will exclusively sponsor the summer music section of the app. Viacom expects to deliver versions of the MTV app for Android and Microsoft Xbox 360 by the end of the year.