Apple gadget lovers hungered for the "next big thing" after the company fired off invitations to a mystery unveiling on September 9.
Fuelling rampant speculation regarding what the company has in store was the fact that the event announced on Thursday will be held in the same performing arts centre in Silicon Valley where late Apple co-founder Steve Jobs introduced the Macintosh computer in 1984.
Flint Centre for the Performing Arts, on a college campus near Apple's headquarters in the California city of Cupertino, has greater seating capacity than venues the company has traditionally used for media events.
Images of the centre posted online showed that a construction project seemingly related to the Apple event was taking shape behind white walls as tall as the building.
A security team guarded the scene.
"Clearly, putting the event in a larger venue and erecting some mysterious building sends cues it is something dramatic and important," Forrester analyst Frank Gillett said of Apple's preparations.
"There is symbolism in that it is the place where the original Mac was introduced."
Apple has remained tight-lipped about what is in store at the event, opting instead to let anticipation, speculation and excitement focus attention on the iPhone, iPad, iPod and Macintosh maker.
"We are all trying to read the tea leaves," Gillett said.
"But September is an excellent time to introduce the iPhone, as well as any new wearable gadget."
The famously secretive company offered scant clues in emailed invitations that showed the September 9 date in large numbers over the words: "Wish we could say more."
Rumours about Apple's plans have been swirling for months, with many observers convinced a new-generation iPhone with a larger screen is on the horizon.
Technology news website Re/code on Wednesday fuelled speculation with a report that Apple would finally embark on a foray into wearable computing.