Apple WWDC 2015 live Blog
The Moscone Center in downtown San Francisco is adorned with Apple's logos ahead of WWDC 2015 where iOS 9 and Apple Music will be launchedTwitter

Apple expects to attract 100 million paying subscribers to its new music streaming service, which will be announced at its WWDC keynote today, 8 June.

That figure overshadows rival Spotify, which has around 60 million subscribers in total, of which only 15 million pay each month. Apple's target, coming from a source speaking to the Associated Press, seems incredibly optimistic. The same source claims Apple will charge $10 (£6.50) per month for music streaming.

To reach that huge number, Apple will reportedly offer a three-month trial period to get users hooked, and will offer the service every time customers buy songs and albums from the iTunes Store.

Currently, around 41 million people globally pay for streaming services like Spotify and Deezer, while subscription revenue grew by 39% in 2014, up to $1.6bn. Download sales fell by 8% to $3.6bn, suggesting the market is moving away from downloads and towards a streaming model, where an unlimited amount of music can be listened to for the flat monthly rate.

iTunes Radio update

Apple's service will be built on Beats Music, which was bought in late 2013 for $3bn. Beats users will be migrated over to the new service, before it is eventually closed down. Apple also plans to bolster its free music offering, iTunes Radio, with a live online radio station featuring DJs like former BBC host Zane Lowe and artists Pharrell, Drake, Muse and David Guetta.

The iPhone maker will need to offer a service more compelling than Spotify, with more music and better features to lure users away. "They are very late to the game on streaming," said Gartner analyst Van Baker, who added that Apple can still catch up by making it easy for its enormous iPhone user base to sign up.

That pool of potential customers is vast and still growing; Apple sold 61 million iPhones in the last quarter alone, and a new model is due to be announced in September, further boosting sales.

Apple will reveal all at its WWDC event in San Francisco this evening. The event kicks off at 6pm GMT and will run for around 90 minutes.