According to 9to5Mac.com, the new feature is called "Time in Bed tracking" and has been given the Codename of Burrito.
Among its uses is measuring quality of sleep, movement, heart rate, and even noises like snoring.
The information will be stored and managed under the Health app and the Sleep app on the wearable smartwatch.
The only downside is that it means the device will have to be worn at night and will require plenty of battery power.
However, owners will be notified that their watch needs charging before going to bed.
More information is hopefully set to be revealed on September 10, when Apple is expected to share the updates coming to the Apple Watch, plus their latest watchOS 6 software.
The new operating system enables users to delete built-in apps.
As recently reported by Tech Crunch, Apple will allow owners to remove many of the first-party features, including Alarm, Timer, Remote, Camera Remote, Stopwatch, Radio and several others.
It's also said users will be able to ditch health apps like Breath, ECG, Noise and Cycle Tracking.
As it stands, Apple Watch uers can easily remove third-party apps they've installed from the App Store, simply by either pressing and holding on the icon and then tapping the X to delete it, or by going into the app settings and turning off the switch saying "Show on Apple Watch".
Users have also been able to remove many built-in apps from their iPhone, but dedicated Watch apps couldn't be removed because there was no iOS equivalent to uninstall.
However, the new update will change that as they'll be available - and thus deletable - in the app store, meaning they can be removed in the knowledge they can be reinstalled at a later date.