Apple sent out invitations Thursday to a media event where it is expected to unveil the anticipated "iPhone 6S." The event will be held at the Bill Graham Civic Auditorium in San Francisco on Sept. 9 starting at 10:00 a.m. PDT.

Invitations sent to the press were topped with the tagline "Hey Siri, give us a hint. And if you ask her, this is her reply:

"You'll have to wait until September 9. I bet you were one of the kids who snuck downstairs to open presents early, weren't you?"

iPhone 6S Siri Asking Siri to give a hint results in this reply. Photo: Apple Inc.

While exact details of the iPhone 6S have yet to be revealed, leaks have hinted to what it may come with. One such feature may be a 12MP camera, according to 9to5Mac.

The upgrade means the iPhone will be able to take larger and higher resolution photos. Since the release of the iPhone 4S in 2011, Apple has upgraded various parts of the iPhone, such as its case design. Its camera also saw some changes in respect to the lens, image stabilization and flash. But what has remained the same up to this point is an 8-megapixel sensor.

Beyond still photography, the iPhone 6S camera is also getting an upgrade with the ability to record 4K video footage -- four times the size of 1080p video the iPhone 6 is capable of shooting. While this is a first for the iPhone, Apple isn’t the first to introduce the capability in smartphones. That title belongs to the Acer and its Liquid S2 launched in 2013. Since then dozens of devices have started to pop up with 4K video recording support -- including Samsung’s Galaxy Note 5 and S6 Edge Plus phablets.

The front FaceTime camera will also receive an upgrade to improve the quality of video chats and selfies, according to 9to5Mac. But no specifics were mentioned on whether that means a higher resolution camera or improved sensor.

In the months leading to the anticipated launch of the iPhone 6S, research notes and rumors have pointed towards an upgrade to a 12MP camera sensor. But that’s not the only feature expected to make its way onto the device. Apple’s iPhone 6S is also expected to come with an A9 processor, 2GB of RAM and a pressure-sensitive Force Touch display.

In addition to iPhones, it’s anticipated to unveil a revamped Apple TV set-top box.