The company has confirmed that it will be available "by invitation and subscription". US users will be able to sign up to test the service today.

Daniel Ek, Founder and CEO of Spotify, said: "We believe that music is the most social thing there is and that's why we've built the best social features into Spotify for easy sharing and the ultimate in music discovery."

Much speculation has surrounded the service's struggles to sell its freemium model - a free ...