The trademark enigmatic invitations said a little more than the time and place of the event, which is the spacious Bill Graham Civic Auditorium near city hall. A line on the invite reading: "Hey Siri, give us a hint," led many to believe that virtual assistant software Siri, which is built into Apple devices, will help people find shows or movies on Apple TV.

Apple TV is also believed to be getting its own App Store, which will be open to outside developers who can make games and other content for it. The third-generation Apple TV was introduced slightly more than three years ago. The California-based company long downplayed Apple TV as a "hobby" after the original version was released in 2007.

"They are finally revisiting their hobby, the Apple TV," said Forrester analyst Frank Gillett.

Apple is dabbling with the idea of making online television programming in a move that would challenge established players such as Netflix and Amazon Prime, according to a recent report in show-business magazine Variety.

"There is a definite movement toward cord-cutting, and Apple is in position to do that," said Gartner analyst Van Baker.