NEW YORK  — With the extension of “Sesame Street” into a high-price neighborhood — HBO, where it premieres Saturday morning — it has signaled significant urban renewal.

“Sesame Street” grew out of the socially progressive ethos of President Lyndon Johnson’s Great Society of the 1960s. Premiering on public television as a breakthrough in children’s TV on Nov. 10, 1969, it was conceived primarily to help prepare underprivileged preschoolers for their entry into the classroom. And this “Street” could be visited toll-free.

Needless to say, the Sixties are long gone.

Now “Sesame Street” is setting off for its 46th season of making kids “smarter, stronger, kinder” (the show’s motto) at its new HBO address.

Those 35 new half-hours won’t begin rolling out on PBS until fall.

In the meantime, the continuing PBS version of “Sesame” has been retrofitted from its traditional hour’s length to “best-of” half-hours drawn from the past few seasons (check local listings for air times).

The five-season deal with HBO, which provides the program with what its producers have called “critical funding,” will make the show available on HBO and related platforms, including HBO GO and HBO on Demand, in both English and Spanish.

The changes afoot reflect the current flood of children’s programming (by contrast, “Sesame” originally filled a niche almost no other kids’ show even recognized), as well as the new ways this umpteenth generation of “Sesame” fans practices viewing habits vastly different from decades ago.

“Sesame” will premiere on HBO on Saturday at 9 a.m. EST with two new half-hours. Episodes will air simultaneously on HBO Latino, and an hour of repeats will air on HBO Family daily at 8 a.m.

This new “Street” represents the “boldest” changes in the program’s history, says Sesame Workshop.

Based on the first two episodes available for preview, those changes go beyond the added media outlet and scaled-down length. The show, perhaps more beautifully produced than ever, is now efficiently packaged in a single theme per episode, rather than the magazine format of its past.

One of this week’s shows addresses “Exploration” (including a sequence with actor Alan Cumming as Mucko Polo, a “grouch explorer” who leads Elmo and fellow Muppets on escapades using their five senses to track down yucky things).

The other episode’s theme is “Bedtime,” as Elmo and Abby Cadabby get help in adopting a calm-down bedtime routine from a new human character, Nina (played by the enormously appealing Suki Lopez).

Expected elements remain Elmo’s Letter of the Day (”B” is for Bedtime) and the Count saluting his Number of the Day.

Cookie Monster has a brand-new feature, “Smart Cookies,” where he and a team of crime-fighting cookie friends thwart the efforts of the villainous Crumb.

As always, star turns are part of “Street” life. Besides “The Good Wife’s” Cumming, bold-face names include Sara Bareilles, Ne-Yo, Tracee Ellis Ross and Gina Rodriguez.

But the biggest star, by far, remains Elmo, who headlines most of the segments and, joined by legions of his fellow Muppets, dominates to the near-exclusion of any human “Sesame” inhabitants. And even moving beyond the physicality of puppets, the episodes make generous use of digital imagery in a seamless abstract integration.

Bottom line: The easygoing pace in the neighborhood of old seems to have fallen prey to a newly revved-up virtual world. A dazzling new opening is set (for the first time) on Sesame Street itself, but in the action that follows, this precious urban retreat is more a state of mind than on-screen real estate.

Even so, it’s hard not to get caught up in the lively, trippy antics of this newly Street-wise show, such as when Elmo performs a musical tribute to guacamole alongside a singing, dancing nose.

And grown-ups sneaking a peek with their kids can still learn from the show they grew up with. By now, have you maybe forgotten what a rhombus is? This week’s “Sesame Street” will school you. If you have HBO.