The secret app on your iPhone revealed

Hackers discovered the Fitness app only became visible when they fooled their phone into thinking it was paired with an apple Watch.

The app allows users to see the fitness data their watch has collected, and to manage it and set their fitness goals. 

It was discovered by developer Hamza Sood.

'So the Fitness app does exist on 8.2, it's just hidden until you connect an Apple Watch,' he tweeted.

The app has already been shown off by apple in the promotinal material for the watch - but it was not known when it would be made available to users.

The iPhone app stores data captured by the Watch, and it can show stats over time as well as achievements. 

Unsurprisingly, the app can share data with the Health app, meaning users can see all their data in one place.

It is also used to control how much music is stored on the phone. 

Apple is preparing for the for the April 24 shipping date of the Apple Watch, which it has pushed as a personal fitness trainer, capable of tracking steps and other metrics, such as heart rate.

On the back of the Watch's case, a ceramic cover with sapphire lenses sits above a sensor that uses infrared and visible-light LEDs and photodiodes to detect the wearer's heart rate. 

Apple Watch uses this sensor, along with an accelerometer and the GPS and Wi‑Fi in a connected iPhone, to measure physical movement such as steps, distance and calories. 

Yesterday Apple removed competing fitness bands from its retail stores as the company prepares to ship the the Apple Watch.

Stores in San Francisco, Palo Alto, Los Angeles and New York reveal Apple no longer carries such popular bands as the Jawbone Up and the Nike+ FuelBand, both activity-tracking wristbands, according to Re/Code.

The devices has also been removed from the firm's online stores. 

Earlier this week Apple shows off the Watch, which includes fitness apps as well as sensors to track heart rate. 

Since its unveiling in September the Watch has been shrouded in mystery, with Apple's boss Tim Cook teasing features at every available opportunity. 

But now everything - including its 'all-day' battery life has been announced - although the CEO added that with typical use this is more likely to be 18 hours. What 'typical' use entails remains unknown.

Prices for the Sport model start at $349 in the US and £299 in the UK, while the stainless steel Watch starts at $549 (£479) and the Edition costs from a staggering $10,000 (£8,000). The most expensive model in the US will cost $17,000 (£11,200). 

Mr Cook said at the event at Yerba Buena Centre in California: 'This is the most personal device we have ever created. It's not just with you, it's on you.'

Apple initially announced its Watch in September at its iPhone 6 and 6 Plus launch event in California.

(dailymail.co.uk)