OnePlus has officially announced its first smartwatch, the OnePlus Watch.

Designed to be affordable but sleek, the Watch has a 46mm circular face with an AMOLED display and uses hand-polished, "premium" materials in its build.

While there are no official details on the proprietary OnePlus operating system as yet, it doesn't run on WearOS. However, it still comes with plenty of built-in features. It supports more than 110 workout types, for example, being able to track pulse, distance, calories, speed and SWOLF efficiency for swimmers.

It has GPS on-board, plus sensors to monitor breathing, stress, blood oxygen saturation and heart rate.

There is 4GB of on-board storage (2GB usable) and can be used to control a OnePlus TV, acting as a separate smart remote control.

Perhaps most importantly for some, extended battery life is offered through the 402mAh battery. Super fast charging can provide a day's worth of power in just five minutes, whereas a 20 minute charge will give you a staggering week's worth of use.

It is fully water and dustproof, rated as IP68. 

There will be two models available, a Classic Edition in white or black and a Cobalt Limited Edition made from cobalt alloy. The watch face on the latter is also protected by sapphire glass.

The OnePlus Watch will be released globally, although we don't yet have an actual release date. It will start at £149 / $159.