With Apple Watch set to hit the market on 24 April, developers have been asked to “prepare and submit their WatchKit app, icon, screenshots, and description for review” by the company.

Details and resources for designing a WatchKit app are given in the Apple Watch Human Interface guidelines on Apple’s website.

It has also published “development tips and guides to build a well-performing WatchKit app, Glance, and actionable notification,” Apple said on its developer blog.

“Before you submit your app, make sure that it adheres to the app review guidelines,” it added.

Once a WatchKit app is approved and released by Apple, existing iPhone users will receive an app update and customers will see the WatchKit extension icon and description on the App Store.

A small group of people who currently have an Apple Watch will be able to use the WatchKit app before 24 April, unless developers set the release date to “manual”.

More than 40 apps have already been updated with support for the Watch support, including big names like Instagram, Twitter, Evernote and TripAdviser.

Last month, it was reported that the Watch may pose limitations for app developers because Apple has blocked features like the gyroscope and accelerometer on the development kit and it is not possible to test all functions on the watch simulator.