Word of such a change had been reported in May.
While the change is optional, the switch conveys the South Korean company's interests in bolstering Tizen so it can reduce its dependence on Android. Samsung is the undisputed leader of Android smartphones, but it still needs an alternative system that gives it more control over its own future. Also, by offering Tizen to more Gear users, Samsung could be creating a bigger audience on the operating system, providing an added incentive for developers to make more apps for Tizen.
Samsung said the switch would provide original Gear users with about 140 apps worldwide -- nearly twice as many as available through Android on the device -- as well as more features to customize fonts, wallpapers, and home screen icons. Owners now will also be able to store music on the smartwatch and play it back directly from the device using Bluetooth headphones.
After Samsung introduced the Galaxy Gear smartwatch in 2013 using Android, it followed up this year with the Gear 2 and Gear 2 Neo using its own Tizen software, which it has been developing for smartphones and other mobile devices.