Users who pay the $9.99 a month for Google Play Music All Access are starting to receive VIP invitations to join the Glass Explorer program. AndroidCentral reports that Mountain View is sending emails out this morning calling for subscribers to sign up for access:

With the launch of Google Play Music on Google Glass, we’ve secured VIP invitations for All Access customers to join the Glass Explorer Program. Interested in rocking out while exploring with Glass? Sign up to receive your invitation below!

Google Glass, currently $1,500, is expected to launch to the general public sometime next year. Google is already ramping up for the release by making hardware tweaks to support prescription lenses and unveiling an accessory store for Glass owners. Even the floating barges at San Francisco's Treasure Island are reportedly retail outlets where customers may soon be able to purchase the headset.

Update: A previous version of this post stated that Glass will cost $1,500 when it launches. That was inaccurate.