Apple has confirmed to the US news outlet The Verge that it will begin making iPhone wallpaper themes available on Apple Watch apps on April 1, and Apple Watch app developers are now able to start accepting the new wallpaper theme.
The Wallpaper app on the Apple Watch already includes the default Apple Watch wallpaper and Apple Pay wallpapers, but now Apple Watch developers will be able to customize the default wallpaper to match their Apple Watch and Apple Music apps.
Apple Watch owners can also now set a wallpaper in their watch app for use on their Apple Watches.
Apple has also revealed that it is planning to make iPhone wallpaper available for developers through the app store.