Spotify has lent its vast 20 million song strong library to Last.fm so that you can play any song Spotify has through the Last.fm website.

You'll no longer need to fire up Spotify or visit the web player to listen to the artists that Last.fm recommends to you - instead, just click the play button on Last.fm itself.

Hitting play will generate a playlist of all the tracks on that particular Last.fm page as a playlist in Spotify - so if you click into the tag 'dark pop', you'll build a playlist of all the songs tagged 'dark pop' on Last.fm. It can get pretty dark in there.

Scrobble ahead

Last.fm was already available on Spotify - not only could you connect your accounts to scrobble everything you play on Spotify through Last.fm, there was also a dedicated Last.fm Spotify app.

The app gives you recommendations based on things you've played recently and generates playlists of songs that are similar to any chosen track.

Happily, free subscribers can make use of the Last.fm tie-in as well as premium ones, although you'll still have to put up with the ads.

The benefit for Last.fm is massive, letting you listen to music on it for free as it used to before it decided that free on-demand music was not really its bag and went paid-for only.

The company has long said it sees Spotify as a collaborator rather than a rival - Spotify, meanwhile, adds another music discovery string to its bow.