Apple has revealed the new iPhone Xs, which it says is the most advanced smartphone ever developed.

The brand new phone comes in a shiny new gold colour and boasts an improved screen.

On the outside, the primary change is the colour: the stainless steel finish is now available in gold as well as the white and black of the existing iPhone X.

(REUTERS)

But on the inside just about everything has changed, including a fast new processor and radical improvements to the Face ID unlocking system.

And there is also a larger version of the iPhone Xs, known as Xs Max. That phone has the biggest ever display on an iPhone – while it is roughly the same size phone as the Plus-sized phones, it has a much bigger display.

On both phones, the camera is vastly improved, according to Apple. Though the hardware didn't seem to have changed, it relies on the new A12 bionic chip that powers the rest of the phone to take much better photos and videos.

(REUTERS)

Both the XS and XS Max are also stubbornly waterproof, and Apple said that they can even be dropped into beer and will continue to work.

(REUTERS)

Apple said the technology inside the phone will help improve the experiences that people can have with, and showed those off using a range of app developers. It invited Bethesda on stage to introduce a new Elder Scrolls game, for instance, and basketball app Homecourt showed how it can use the augmented reality features to help people practise shooting.

Apple is currently unable to embed an eSIM into its devices in China, so they will release a special iPhone XS and XS Max for the country. With these versions, you will be able to insert two SIM cards at once.

The iPhone XS starts at $999, or the same in pounds -- the exact same price as the X went on sale for last year. The larger XS Max costs $1099, the most Apple has ever charged for an iPhone.

iPhone XS launch in September 2018 Show all 11 1 /11 iPhone XS launch in September 2018 iPhone XS launch in September 2018 Tim Cook speaks about the iPhone XS and XS Max Tim Cook, CEO of Apple, speaks about the iPhone XS and XS Max at an Apple Inc product launch event REUTERS iPhone XS launch in September 2018 Tim Cook speaking at the iPhone launch Tim Cook, CEO of Apple, speaks on stage at the end of the Apple Inc REUTERS iPhone XS launch in September 2018 Tim Cook speaking during the event Tim Cook speaks during an Apple event AFP/Getty Images iPhone XS launch in September 2018 Phil Schiller, Apple's senior vice president of worldwide marketing Phil Schiller, Apple's senior vice president of worldwide marketing, speaks about the Apple iPhone XS and Apple iPhone XS Max AP iPhone XS launch in September 2018 Phil Schiller speaks about the new iPhone XR Philip W. Schiller, Senior Vice President, Worldwide Marketing of Apple, speaks about the new Apple iPhone XR REUTERS iPhone XS launch in September 2018 Range of new Apple products Phil Schiller, Apple's senior vice president of worldwide marketing, speaks about the new Apple iPhone XS, iPhone XS Max AP iPhone XS launch in September 2018 The iPhone XR Philip W. Schiller, Senior Vice President, Worldwide Marketing of Apple, speaks about the new Apple iPhone XR REUTERS iPhone XS launch in September 2018 Apple COO Jeff Williams talking about Apple Watch Series 4 Apple COO Jeff Williams discusses Apple Watch Series 4 AFP/Getty Images iPhone XS launch in September 2018 Apple COO Jeff Williams talking about Apple Watch Series 4 Jeff Williams, Chief Operating Officer of Apple, speaks about the the new Apple Watch Series 4 REUTERS iPhone XS launch in September 2018 Apple COO Jeff Williams talking about Apple Watch Series 4 Jeff Williams, Chief Operating Officer of Apple, speaks about the the new Apple Watch Series 4 REUTERS iPhone XS launch in September 2018 Former NBA player Steve Nash and Todd Howard, Former NBA player Steve Nash and Todd Howard, Game Director, speaks on stage at an Apple Inc REUTERS