The service is backed by iTunes Match-rivalling cloud features, allowing users to add up to 20,000 songs from their existing collection to the cloud for streaming on Android devices or a web browser.
Customers' music collections will be scanned and any tracks that match an existing song in the Google Play catalogue will be automatically added to their online library without the need to upload it, as part of a free service.
The internet giant also announced that it has secured a partnership with Twentieth Century Fox to add its movies to Google Play, and Warner Music Group to expand its music archive.
Google expanded its storefront to coincide with the unveiling of its latest Nexus products - the Nexus 10 tablet, the Nexus 4 smartphone, and the 32GB and 3G models of the Nexus 7 slate.
Google Play's music section will be accessible in the UK from November 13.
Watch a video introducing Google's new Nexus line below: