One of the popular features of the Apple Watch is activity tracking, helping wearers track the calories they burn, distance they go, and more while they’re working out. Now a new report says that Apple is working to expand its activity tracking to include a new feature.

Apple is reportedly working on adding Sleep Tracking to the Apple Watch. The feature is codenamed “Burrito”, say sources speaking to 9to5Mac, and it’s called “Time in Bed tracking” internally. When enabled, the feature will track your sleep using input like movement, heart rate, and noises, and it’ll upload this info in your Health app and a new Sleep app in the Apple Watch.

Lots of Apple Watch owners charge their Apple Watch overnight and put it on in the morning, but Apple has reportedly created a feature that’ll remind wearers to charge their Apple Watch before bedtime so it’ll last through the night. People with more than one Apple Watch can designate one as their bedtime Apple Watch.

Finally, if a person wears their Apple Watch during bedtime and gets up before their alarm, the Apple Watch will automatically turn off the alarm. An alarm will only play on the Apple Watch, and there will reportedly be a silent alarm option that’ll only vibrate the Apple Watch. Do Not Disturb mode will be automatically enabled when the Apple Watch wearer goes to bed.

Today’s report says that this sleep tracking feature won’t require any special hardware to work. It’s not known if it’ll require a new Apple Watch model, but that’s not expected to be the case.

Apple is hosting an event on September 10, so it’s possible that this new sleep tracking feature will be announced there.

There are other smartwatches on the market that offer sleep tracking, and there are even some third-party Apple Watch apps that’ll tracking your sleep for you. Building sleep tracking into the Apple Watch would be a smart move for Apple because it’d likely make the device more attractive to folks with a built-in sleep tracker made by Apple, but it’ll be interesting to what the battery life is like with it enabled and if consumers are willing to adjust their charging habits to use it.

Do you track your sleep with a smartwatch?