Google's YouTube is starting a subscription service that allows users to stream ad-free music videos and to download them for offline use.
The £9.99 monthly fee for Music Key also provides membership to Google Play All Access, the firm's existing "all-you-can-eat" song download facility.
It is set to pose a challenge to Spotify, Rdio, Beats Music and other audio-only "unlimited" music services.
The launch had been delayed by a dispute with independent labels.
However, Google said it had now signed deals with hundreds of indies worldwide.
