Google's YouTube is rolling out the long-awaited paid monthly subscription service called YouTube Music Key.

The subscription for the ad-free service will start at $7.99 per month and will allow users to watch videos offline and listen to music while other apps are working.

YouTube Music Key will be first available through an invite to its "biggest music fans", who can try out the beta version for six months at no charge, YouTube said in its blog.

The fee will also include a subscription to Google Play Music. – Reuters