LOS ANGELES — It’s Not TV. It’s HBO.

For more than a decade, that was the slogan for the premium cable channel that gave the world “The Sopranos” and other fare that could not be aired by the major television networks.

Now, with AT&T as its new corporate parent, and a streaming service called HBO Max planned for 2020, the HBO name is becoming synonymous with big network sitcoms and mainstream television stars.

In July, HBO Max nailed down the exclusive streaming rights to all 236 episodes of “Friends,” the prime-time NBC sitcom of the 1990s and 2000s that has had a surprisingly remunerative second life in syndication and as a streaming show.

This month, HBO Max won the exclusive rights to 279 episodes of another durable sitcom, the CBS stalwart “The Big Bang Theory,” which ended its prime time run in the spring as the ratings leader among network entertainment shows for the 2018-2019 television season.