Apple will launch two new iPhones and a larger, more powerful iPad later this week, according to reports.
Apple watchers also expect that the much-anticipated iPad Pro, a larger version of Apple's tablet that will have power similar to a laptop and a 12.9in screen, could be confirmed at the event in San Francisco tomorrow.
A switch of venue from the Moscone Centre to the Bill Graham Civic Auditorium, which can hold 7,000 people, has been interpreted as a sign that Apple will have a bumper number of announcements to make this year. The new venue also happens to be the same hall in which the late Steve Jobs unveiled the Apple II computer in 1977.
The next version of Apple's mobile operating system iOS 9 is likely to be released alongside the new iPhones and new straps for the firm's wearable offering Apple Watch have also been touted as potential announcements.
The firm's Apple TV media streaming box is due to get its first update in three years, with strong rumours suggesting that an App Store will be introduced to the device for the first time, as well as a new remote control that includes digital assistant Siri, enabling users to search using their voice. A gaming aspect to Apple TV has also been widely predicted.
The technology giant is said to be aiming to repeat or even exceed last year's demand for the iPhone 6 and 6 Plus this year, which received four million pre-orders on the first day and sold more than 70 million in three months, resulting in Apple recording the largest-ever quarterly profit from a public company at £11.8bn.
Apple September 2015 event infographic
Apple event infographic, September 2015